UPDATE 8:21 p.m.- BOSTON (AP) -- Police say at least three people have been killed in the explosions near the finish line of the Boston Marathon.Police commissioner Ed Davis confirmed the three deaths but provided no details.The explosions Monday also injured more than 130 people, knocking spectators and at least one runner off their feet.Some of the victims lost arms and legs. Other injuries included broken bones, shrapnel wounds and ruptured eardrums.
UPDATE 5:15 p.m. - WASHINGTON (AP) -- President Barack Obama, responding to the explosions at the Boston Marathon, says the United States does not know "who did this or why" but vowed that whoever is responsible "will feel the full weight of justice." He said: "We will find out who did this and we will hold them accountable."
UPDATE 4:35 p.m - Google has established a person-finder related to the Boston bombings. Those who are looking for someone or have information about anyone can make reports there.
UPDATE 4:30 p.m. - WASHINGTON (AP) -- President Barack Obama will issue a statement on the explosions at the Boston Marathon in televised remarks to the nation from the White House. Obama was briefed on Monday's explosions by FBI Director Robert Mueller (MUHL'-ur) and Homeland Security Secretary Janet Napolitano (neh-pahl-ih-TAN'-oh). The White House said the president also spoke with Massachusetts Gov. Deval Patrick and Boston Mayor Tom Menino and pledged to provide whatever federal support was needed in responding to the incident.Obama has been monitoring the situation in Boston since news of the explosions first broke.
UPDATE 4:14 p.m. - WASHINGTON (AP) -- Cellphone companies say service is operating in the Boston area, but with heavy traffic following of the explosions at the Boston Marathon.A law enforcement official, citing an intelligence briefing, said cellphone service had been shut down Monday in the Boston area to prevent any potential remote detonations of explosives.But officials with Verizon Wireless and Sprint Nextel said there had been no such requests.Sprint spokeswoman Crystal Davis said: "Minus some mild call blocking on our Boston network due to increased traffic, our service is operating normally."
UPDATE 3:59 p.m.- WASHINGTON (AP) -- The Secret Service says it has expanded its security perimeter at the White House following the explosions at the Boston Marathon.Secret Service spokesman Ed Donovan says the measure was taken "out of an abundance of caution." He says it is not unusual to expand or contract the security perimeters.Shortly after the explosions Monday, Secret Service shut down Pennsylvania Avenue outside the White House, cordoning off the area with yellow police tape. Several Secret Service patrol cars also blocked off the entry points to the road.The White House was not on lockdown and tourists and other onlookers were still able to be in the park across the street from the executive mansion.
UPDATE 3:42 p.m. - CBS News reporting a police source says they believe the explosives at the Boston Marathon were planted in trash cans. Same source also told CBS News they believe they have surveillance video of a possible suspect- a man carrying multiple backpacks. Still waiting on press conference with Boston Police.
UPDATE 3:23 p.m. - WASHINGTON (AP) -- Intelligence official: 2 more explosive devices found at Boston Marathon; being dismantled.
UPDATE 3:09 p.m. - Boston Police confirming two people are dead and at least 23 injured after two explosions at the Boston Marathon. Marathon officials claiming the explosions were caused by "bombs," but police are not confirming yet.
UPDATE 2:59 p.m. - WASHINGTON (AP) -- The White House says President Barack Obama has been notified about the explosions at the finish line of the Boston Marathon.
The White House says the administration is in contact with state and local authorities and directed his administration to provide whatever assistance is necessary in the investigation and response.
Vice President Joe Biden was on a conference call with gun control activists when staffers turned on televisions in his office Monday to view coverage of the explosions. Biden said during the call that his prayers were with those who suffered injuries.
UPDATE 2:56 p.m. - A CBS News producer at the scene just reported she heard a third explosion. However, she added that police warned those at the scene they would hear a loud explosion. She said she asked police if it was a bomb, and he reportedly nodded his head "yes".
UPDATE 2:37 p.m. - BOSTON (AP) -- Spectators and runners are describing the twin explosions that shook the finish line of the Boston Marathon today.
One woman says she was waiting for her husband to cross the finish line, and, in her words, "it just blew." She described it as "a loud boom, and then glass everywhere." Cherie Falgoust says something hit her head, and she "just ducked."
A runner, Laura McLean of Toronto, says she heard two explosions outside the medical tent. She says, "There are people who are really, really bloody." McLean says, "they were pulling them into the medical tent."
The explosions took place about three hours after the winners crossed the finish line. The second one could be heard a few seconds after the first one.
A runner said, "There are a lot of people down."
Marathon workers were seen carrying one woman, who did not appear to be a runner, to the medical area as blood gushed from her leg.
UPDATE 2:20 p.m. - (AP) - Two explosions at the finish line of the Boston Marathon have resulted in injuries. Bloody spectators were being carried Monday to the medical tent that had been set up to care for fatigued runners. Police wove through competitors as they ran back toward the course.
BOSTON (AP) -- Authorities are investigating a report of two explosions at the finish line of the Boston Marathon.
There were two booms heard from near the finish line inside the Fairmount Copley Plaza Hotel.
Race officials locked down the hotel because of the report.
The sound of two booms, which sounded like thunder, had come a short time earlier.