**SEE UPDATES FOR BREAKING DEVELOPMENTS**
Terror in Boston, with (verified and unverified) reports flooding the zone by the second. As of this moment, we know that authorities believe two powerful explosions were detonated in fairly rapid succession near the finish line of the Boston marathon earlier this afternoon. Dozens have been injured, and there are conflicting reports of fatalities. Twelve dead? Three? None? Boston police say they've detonated a third "controlled explosion," and several downtown Boston hotels have been evacuated. Here's terrifying early video of the first explosion:
Some images of the resulting carnage immediately flashed across Twitter; the photos are graphic and disturbing. No one can confirm if this is an act of terrorism -- and if so, by whom. Initial details are sketchy, but some certainly point to a possible terrorism link: Back-to-back detonations at a crowded, high-profile public event sounds awfully deliberate. It's important not to jump to any conclusions during these early stages, but the terrorism question is undoubtedly on many Americans' minds. More details as they come...
UPDATE - CNN has confirmed at least two deaths.
UPDATE II - IED's = improvised explosive device = terrorism, if true:
NBC: Law enforcement officials who spoke to @nbcnews believe the explosion was at least 1 small IED - a homemade bomb— Sarah Boxer (@Sarah_Boxer) April 15, 2013
There are no reports regarding claims of responsibility or possible motive -- *if* this is terrorism.
UPDATE III - Thus begins the shameless, knee-jerk politicization:
explosion is a reminder that ATF needs a director. Shame on Senate Republicans for blocking apptment articles.washingtonpost.com/2013-02-01/wor…— Nicholas Kristof (@NickKristof) April 15, 2013
UPDATE IV - Precautionary safety measures at the White House.
UPDATE V - Multiple devices found, per NBC News:
BREAKING: Multiple explosive devices found, at least 2 which exploded, officials tell NBC News— NBC Nightly News (@nbcnightlynews) April 15, 2013
UPDATE VI - Associated Press: Two unexploded bombs found in Boston, being dismantled by police. This absolutely has all the hallmarks of a coordinated terrorist attack. ABC News is now reporting that police are concerned the devices may have been triggered by cell phones. NEW: Ball bearings in the explosive devices? CBS: "Hell yes they are bombs."
UPDATE VIII - Boston's Police Commissioner confirms three "incidents," calls the attack an "ongoing event" moments ago at a press conference. Says there was a third explosion at the JFK Presidential Library that they believe "was related." Asked if this is a terrorist attack, the commissioner told viewers to "draw your own conclusions."
UPDATE IX - The NY Post -- again, with an exclusive -- is reporting that the alleged suspect is a Saudi national.
UPDATE X - Oh God. Video of both explosions.
UPDATE XI - Boston PD now backing away from the claim that the third explosion was related. It may have just been an accidental fire across the city. CBS News has some interesting new details:
According to CBS News correspondent Bob Orr, two bombs were inside trash cans near the viewing area close to the finish line. One unexploded device has been recovered, according to CBS. Orr is reporting that authorities have recovered surveillance video from the area which shows a man with what looked to be two backpacks near the scene just moments before the blast.
No one has confirmed the Post's story that there's a Saudi national in custody, though they've updated their reporting to add that this individual is 20 years old. Fox News
has confirmed quotes a source saying there's a person of interest being "guarded" at a Boston hospital. NEW: Now NBC News, too.
NBC News: Boston Police are "guarding" a wounded man at a Boston hospital as a "possible suspect" in the blast— Jesse Rodriguez (@JesseRodriguez) April 15, 2013
The NY Post had this first, with Fox News and NBC following. We'll see if the Post is also right about the nationality of the suspect. Multiple networks now officially labeling today's events a terrorist attack. President Obama will address the nation just after 6pm ET.
UPDATE XII (Kevin): The Boston police have disputed the New York Post's account of a suspect being held in custody.
In a 6:10 pm EDT statement from the White House, President Obama addressed what increasingly looks to be an attack, though stopped short of calling it terrorism. "On days like this there are no Republicans and Democrats. We still do not know who did this or why. Any responsible individuals or responsible groups," the President said, "will feel the full weight of justice."
UPDATE XIII (Guy) - CBS News is now echoing the Post's reporting about a Saudi national being held as a person of interest in these attacks:
JUST IN: @johnmillercbs reports that individual is in custody after Boston blast, a Saudi national. Reported cooperative/denies involvement.— CBS News (@CBSNews) April 15, 2013
A Boston news station and NBC News are reporting that an eight-year-old child is among the dead. Horrific.
UPDATE XIV (Kevin) - The death toll has now risen to three people dead and almost 150 people injured - many of them severely. Initial reports surfaced that investigators had found five additional unexploded devices, but the Wall Street Journal now writes that those may be unconnected to the initial explosions:
Counterterrorism officials found five additional suspect devices, but a law-enforcement official said late Monday that investigators now doubt the devices were bombs.
In a 10pm press conference, medical professionals held a press conference and announced that they're working at full capacity and expect to use a lot of blood - and said they'll need all the blood they can get. Time Magazine has a good roundup of how to donate blood if you or anyone you know is in the Boston area.