Picking up from Allahpundit’s thread, we so far have one White House official calling this an act of terror, and reports that there were up to five devices triggered remotely. The Associated Press has the latest injury count:

Update: Rep. Mike McCaul, the House Homeland Security Committee chairman, noted on Fox News that if the reports of ball bearings are indeed true, “I would consider that a significant factor in terms of this being a sort IED device that’s very similar to what the terrorists used overseas in the Middle East.”

Update: I have no words.

The head of an extremist Jordanian Muslim Salafi group said early Tuesday that he was “happy to see the horror in America” after the explosions in Boston.

“American blood isn’t more precious than Muslim blood,” said Mohammad al-Chalabi, who was convicted in an al-Qaida-linked plot to attack U.S. and other Western diplomatic missions in Jordan in 2003.

Update: Boston’s mayor is getting ready to speak; watch it live here.

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And:

Update: Report from NBC that there’s still no definite suspect in custody:

Update: Michael Moore adds his input. Unbelievable.

Update: No changes in D.C.’s plans so far, per Politico:

D.C. Mayor Vincent Gray assured the public at a press conference Monday that Emancipation Day celebrations will continue as usual, though security measures will be heightened as a matter of course.

“We have no changes in plans at this stage. We hope people will continue to come down and engage in this important celebration,” Gray said. “We plan to go forward as we planned prior to this incident in Boston.” …

“We don’t know any information that would suggest that there’s a specific threat…in the District of Colombia,” he said. “But we believe that we’re well prepared to be able to defend the 632,000 people who live here and the many thousands of people who visit this city especially during this time of year.”

Update: The Pentagon has a Navy bomb squad to the scene to help:

The Navy has sent one of its bomb-disposal units to Boston to assist local authorities as needed in the aftermath of the two explosions near the Boston Marathon’s finish line. The blasts killed two and injured more than 100. The three-member explosive ordnance disposal team based at Naval Station Newport, R.I., was sent to Massachusetts after state officials asked for help.

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Update:

Update: The AP is reporting that 124 are injured, 15 critically.

Update: From the WSJ:

Sen. Susan Collins (R., Maine), an intelligence committee member and former chairman of the Senate Homeland Security Committee said: “I believe the attacks bear all the hallmarks of a terrorist attack.’’

Update: CNN is increasing the injury count to 132 people, 17 of them critically, and a source tells them that doctors are pulling ball bearings out of people.

[Update, 7:57 p.m. ET] Doctors are “pulling ball bearings out of people in the emergency room,” a terrorism expert briefed on the investigation told CNN’s Deborah Feyerick.

The same source said the blasts resulted in at least 10 lost limbs.

Update:

Update: Statement from DHS Secretary Napolitano:

“Our thoughts and prayers go out to everyone impacted by this incident in Boston, especially the families and loved ones of those injured. Federal, state, and local law enforcement agencies continue to respond and at the President’s direction, the Department of Homeland Security is providing any support necessary in this ongoing investigation. We encourage the public to be vigilant, and to listen to direction from state and local officials.”

Update: The WSJ reports that authorities have now found five devices that never went off, which makes for a total of seven devices including the two explosions:

Update: Gov. Deval Patrick just spoke, confirming that the FBI is has taken over the investigation, and that there will be a heightened law enforcement presence in Boston tomorrow.

Update: The Boston police report that the death toll has gone up from two to three:

And that there is no definite suspect at Brigham and Women’s Hospital:

Per CNN:

[Update, 8:55 p.m. ET] A Saudi national with a leg wound was under guard at a Boston hospital in connection with the bombings at the Boston Marathon, but investigators cannot say he is involved at this time and he is not in custody, a law enforcement official said Monday evening.

Update: New reports coming in that those five suspicious devices might not, in fact, have been bombs:

Update: Hmmm — another press conference on the way?

Update: Per Fox25, A doctor from Brigham and Women’s Hospital just confirmed that they have treated several dozen of the explosions’ victims for injuries consistent with a heavy blast, but haven’t had any fatalities at their hospital.

Update: And another surgeon at Mass General Hospital confirms that 8 of their patients are currently in critical condition:

[Update, 10:07 p.m. ET] Dr. Peter Fagenholz told reporters that there were 29 wounded people at Massachusetts General Hospital, eight of whom were in critical condition. Many of the people had shrapnel injuries to their lower extremites, he said.

“We have performed several amputations,” he said.