jhonluwis: 2 dead, at least 100 injured in Boston Marathon bombing

At least 105 people are injured and two dead after two bombs exploded near the finish line of the Boston Marathon Monday afternoon. The injuries include dismemberment, witnesses said, and local hospitals say they are treating shrapnel wounds, open fractures and limb injuries. An eight-year-old boy is one of the two known dead, multiple news outlets reported, and several of the injured are also children.

Authorities are telling Boston residents to stay home and avoid crowds as they try to "stabilize" the situation.

"We recommend to people that they stay home," Boston Police Commissioner Edward Davis said at a brief press conference Monday afternoon. "We want to make sure that we completely stabilize the situation."

"We are asking that people ... calmly make their way home," Gov. Deval Patrick said.

Davis said Boston police were not aware of any specific threat to the marathon before it began. Police have no one in custody, but are questioning many people.

Two large explosions, just 50 yards apart, went off shortly before 3 p.m. ET, more than four hours into the race. One of the explosions happened near the entrance of the Fairmont Copley Hotel in Copley Square. The blast scattered hundreds of onlookers and runners, and left a bloody scene of injured spectators, including children. Local news reporter Jackie Bruno wrote that she saw some people with their limbs blown off. The Boston Police Department said it is looking for video footage taken from the finish line as part of its investigation.

Boston Medical Center took in 20 patients, including two children, most of whom are being treated for "lower leg injuries," a spokeswoman said. A spokeswoman for Tufts Medical Center said the hospital is treating nine patients for conditions such as shrapnel wounds, ruptured ear drums, and "serious orthopedic and neuromuscular trauma to the lower legs."

President Barack Obama warned Americans in a brief statement Monday evening not to jump to conclusions before authorities find out who committed the act. "We will find out who did this," Obama said. "Any responsible individuals, any responsible groups will feel the full weight of justice." A White House official said the incident is being treated as an act of terror.

NBC News, citing anonymous law enforcement sources, reported Monday that a "small homemade bomb" is believed to be responsible for the explosion. Authorities found and dismantled at least two more explosive devices. The FAA has created a no-fly zone around the area, and the Boston subway was shut down. Cell phone service was shut down in the area, the AP reported, to prevent any remote detonations. Family and friends of marathon runners or spectators can call 617-635-4500 for information.

This video from the Boston Globe shows the moment the bomb went off, and the paper has also pulled together dramatic photos from the aftermath. According to marathon officials, several thousand runners had not finished the race when the explosions detonated.

Police have evacuated the area on Boylston Street to continue sweeping for more devices. Runners who had not yet finished the race were stopped at mile 25 and directed to Boston Common. The Boston Police Department is calling in all off duty officers in the city. This New York Times map shows where on the route the explosions took place.

Patrick called it a "horrific day in Boston" in a statement.

The New York Police Department is stepping up security around the city in response to the explosion. At the White House, yellow police tape was used to block off Pennsylvania Avenue from pedestrians in front of the White House's north gates and secret service were positioned along the perimeter. Credentialed pass holders continued to be permitted entry and exit from both the White House and the Executive Office Building.

A photo of the apparent explosion posted on Twitter (photo via Boston to A T)