President Obama talks on the phone with FBI Director Mueller about the bombings. (Official White House Photo by Pete Souza)

Earlier this evening, President Barack Obama addressed the nation about the deadly bombing of the Boston Marathon. And, while extending his condolences, the president urged the American public to avoid jumping to conclusions—terrorism, unmentioned by Mr. Obama, seemingly being the most obvious—as the devastation is investigated.

"We still do not know who did this or why and people shouldn't jump to conclusions before we have all of the facts," Mr. Obama explained. "But, make no mistake, we will get to the bottom of this. And we will find out who did this. We'll find out why they did this. Any responsible individuals—any responsible groups—will feel the full weight of justice."

Mr. Obama also said that he's mobilizing the federal government to assist local governments respond and investigate the apparent attack, as well as increasing "security around the United States as necessary."

A man is loaded into an ambulance after the explosions. (Photo by Jim Rogash/Getty Images)

"I've directed the full resources of the federal government to help state and local authorities protect our people, increase security around the United States as necessary and investigate what happened," he said.  "I've also spoken with Governor Patrick and Mayor Menino and maid it clear that they will have every single federal resource necessary to care for the victims and counsel the families. And, above all, I made it clear to them that all Americans stand with the people of Boston."

Mr. Obama, sending his sympathies to the victims, further provided a post-partisan message of unity as Boston recovers.

"I've updated leaders of Congress in both parties and we reaffirmed that on days like this, there are no Republicans or Democrats; we are Americans united in concern for our fellow citizens," he said. "Boston is a tough and resilient town; so are its people. I'm supremely confident that Bostonians will pull together, take care of each other and move forward as one proud city. And, as they do, the American people will be with them."

(Photo: Anna Silman)

Earlier today, multiple bombs went off at the finish line of the Boston Marathon, killing at least two and injuring dozens more.

New York City has already stepped up its own security efforts in case there is a plot to attack additional cities, Mayor Michael Bloomberg announced.

“[T]he NYPD has stepped up security at strategic locations and critical infrastructure, including our subways," the mayor said in a statement.

"Some of the security steps we are taking may be noticeable, including deployment of Critical Response Vehicles and additional police personnel, and others will not be. We have 1,000 members of the NYPD assigned to counter-terrorism duties, and they – along with the entire NYPD and the investments we have made in counter-terrorism infrastructure – are being fully mobilized to protect our city.”

Governor Andrew Cuomo issued his own statement announcing that all state agencies are on "a heightened state of alert as we learn more about this incident," the facts of which are still emerging.

"I have directed state agencies, including the Division of Homeland Security and Emergency Services, State Police, the MTA and the Port Authority, to be on a heightened state of alert as we learn more about this incident," Mr. Cuomo said.

(Photo: Anna Silman)

"New York National Guard on Sunday sent three vehicles and 6 soldiers to support the Marathon, and they are on hand to assist with emergency response and work together with local authorities following this incident."

Several other cities, including Washington D.C., have begun taking similar steps to secure landmarks and high-trafficked areas.

In Times Square, bystanders were frightened by the news and the heightened police presence.

Kirsten Andrews and Lauren Adamo, visitors from Maine, had been following the news for the past hour in their hotel room and came out to observe the scene in the square.

“I wanted to come down and talk to a cop and see if they have a plan in motion if anything happened right now, because it would be chaotic," said Ms. Andrews. "I’m wondering why subways and buses are still running."

Ms. Adamo was concerned about the possibility of more explosions. “My stepdad’s in the military and he says all big cities are under threat right now,” said Ms. Adamo. “It’s a little unsettling.”

A man is loaded into an ambulance after he was injured by one of two bombs exploded during the 117th Boston Marathon near Copley Square on April 15, 2013 in Boston, Massachusetts. (Getty Images)

The Boston Marathon was interrupted this afternoon by multiple large explosions, killing at least two attendees and injuring dozens more, according to the Boston Police Department.

The New York Post is reporting that as many as a dozen have been killed, with fifty injured, but other outlets are currently more conservative in their estimates.

The three blasts, which took place near the marathon's finish line, occurred about four hours after the start of the men’s race, according to The New York Times. The Associated Press reported that additional explosive devices were found near the event and are being dismantled.

"There were two bombs that exploded near the finish line in today's Boston Marathon," the organizing body behind the race said today on their Facebook page. Runners and spectators have been redirected from the blast area as law enforcement officials secured the scene.

Initial accounts described the devastation as extremely serious. "It was huge. There had to be people killed. There had to be," a witness told the  The Boston Globe. Another said there was "blood everywhere."

Massachusetts Governor Deval Patrick issued a statement earlier today, urging people to stay away from the area.

“This is a horrific day in Boston. My thoughts and prayers are with those who have been injured. I have been in touch with the President, Mayor Menino and our public safety leaders," he said.

"Our focus is on making sure that the area around Copley Square is safe and secured. I am asking everyone to stay away from Copley Square and let the first responders do their jobs."

Steven Saurbier, who saw the explosion's aftermath from his window, described a grisly scene to The Observer.

"It shook my building, we're about 100 yards down the street. I figured it was a cannon, or some giant confetti blast, or something planned for the Marathon. Then a second blast went off--much larger--and it rattled the whole building," he said.

"There was a large cloud of white smoke and people were running from the blast site. Police swarmed immediately, they removed one or two people after patting them down. There were a lot of injured people ... I estimate 20 people were medically transported. ... I saw a woman being carried by two men and I am almost positive her left leg was blown off at the knee."

Mr. Saurbier further said it wasn't clear what had caused the initial explosion, but there was a "black crater" left on the sidewalk.

“The blast was on the sidewalk outside of a restaurant. It looks like there is a black crater about a meter radius,” he continued. “There was no fire, no black smoke.”

A man is loaded into an ambulance after he was injured by one of two bombs exploded during the 117th Boston Marathon near Copley Square on April 15, 2013 in Boston, Massachusetts. (Getty Images)

Photographs of police and other emergency personnel on the scene have already begun appearing on Twitter, organized by the hashtag #BostonMarathon.

This post will be updated as additional news arrives.

Apparently, yes.

Fox News Network's favorite alternative proper noun spelling Megyn Kelly was on today, discussing a train derailment in Columbus, Ohio, when the broadcast rolled a clip of citizen journalism video, with the video's cameraman delivering a fairly astute observation of the massive explosion he'd just witnessed.

And yet, Kelly felt the need to apologize for it, and on a subsequent viewing, the 'bad words' were censored:

News Corp's other notoriously conservative news outfits don't seem to shy away from it. Question: Does this say more about Ms. Kelly, the network's viewership, or who someone with Fox News' censor button answers to?

fkamer@observer.com | @weareyourfek

Or some of us just live in Queens and Brooklyn, and don't want to haul ourselves to the other side of Manhattan to watch fireworks that for all intents and purposes should belong exclusively to New Yorkers but still have to share with New Jersey for some reason. And that seems to be quite a few people, no? Yet: Macy's, year after year, has continued their tradition of exploding colored gunpowder over the Hudson River ever year, instead of the East River.

Until now. Hopefully. Because we have someone advocating for us.

With a website.

Yes, public advocate Bill de Blasio has taken up The People's Cause along with superhero-sounding State Senator Daniel Squadron and Marty Markowitz (who would campaign with Spider Man as his running mate if he could do such a thing, utilitarian that he is) have teamed up to take on the persecution of outer-borough residents from receiving the fireworks we so deserve for having to put up with Macy's and all the irritating tourists who seem to congregate around their stores, which are usually in some of our most trafficked pedestrian areas.

Now, you may be thinking: What a frivolous way for a politician to spend their time! You are probably not from New York, where advocacy for ostensibly frivolous things on behalf of our politicians is pretty standard. For context, this is like the opposite of what Sen. Chuck "Fun Destroyer" Schumer does.

Anyway, they have a petition you can sign. Do it before July 4th or else we will all die of sadness and New Jersey will win again.

fkamer@observer.com | @weareyourfek

Rising in the place of the Greek Revival townhouse is a somewhat oddball structure that subtly reference the home's violent history, built in 1978 by architect Hugh Hardy and Steuben Glass executive Francis Mason. It has belonged to the Langworthy family—who famously kept a Paddington bear with a frequently-changing wardrobe in the front window (he's now wearing a Corcoran t-shirt)—since its construction. Now listed for $10.9 million with Corcoran brokers Sara Gelbard and Paul Kolbusz, the home is certainly a "one-of-a-kind home" as the listing, which was also spotted by Curbed, boasts.

It was here that trust fund revolutionary Cathy Wilkerson grew up. But rather than turn her back on her privileged background, she decided to use it to her advantage, asking her parents if she could use the place while they vacationed in St. Kitts. They probably expected to come back to find the carpet a little worse for the wear, rather than returning to find no house at all.

The radical group was building nail-and-dynamite pipe bombs that were to be used to destroy property, including the Columbia library, when one accidentally detonated, instantly killing the three people in the basement.

Wilkerson and her friend Kathy Boudin, who were upstairs at the time, managed to escape, and as described in the wonderfully detailed story published in The Times, came running out of the house covered in soot, mostly naked, their clothes having been torn off in the blast. After showering at a neighbors house, they fled, and did not resurface until years later.

So what's the new place like? It bears little resemblance to the three other Greek Revival townhouse that Henry Brevoort Jr. built for his children in the mid-1800s, but it's certainly more interesting. Designed around an open central staircase, the home also has an elevator, dumbwaiter, three bedrooms and a private guest suite with a full-kitchen.

Light banishes the ghosts of the past, streaming in through big picture windows and a central skylight. Distorted angles and open spaces abound, allowing for great views of the leafy street. There's also a south-facing garden and a 45-year-old Japanese Katsura tree.

And, looking on the bright side, among the residents who lived happy lives at 18 West 11th Street: Merrill-Lynch co-founder Charles Merrill, his son, the poet James Merrill and Broadway lyricist and movie executive Howard Dietz.

kvelsey@observer.com