President Obama talks on the phone to FBI Director Robert Mueller about the explosions in Boston on Monday as chief of staff Denis McDonough and homeland security and counterterrorism advisor Lisa Monaco look on.(Photo: Pete Souza, The White House)
(USA TODAY) -- President Obama vowed on Monday night to get to the bottom of who is behind a pair of deadly explosions near the finish line of the Boston Marathon, but warned Americans not jump to any conclusions.
"We still do not know who did this, or why," Obama said in a brief statement to reporters hours after the deadly explosions at the iconic American sporting event. "But make no mistake, we will get to the bottom of this."
Obama was notified about the blasts at about 3 p.m., and administration officials have been coordinating with Massachusetts and Boston authorities, according to a White House official.
Obama spoke with Boston Mayor Tom Menino and Massachusetts Gov. Deval Patrick and told them that he was ready offer Boston any support in needs to respond to the incident.
Obama later was briefed by FBI Director Robert Mueller and Department of Homeland Security Secretary Janet Napolitano on the investigation and response to the incident in Boston. The president also spoke to House Speaker John Boehner and Senate Minority Leader Mitch McConnell.
Boehner ordered American flags to be lowered outside the U.S. capitol to half-staff on Friday evening.
"Words cannot begin to express our sorrow for the families who are grieving so suddenly right now," Boehner said. "The House of Representatives offers its prayers to the victims and the city of Boston. We also give thanks for the professionals and Good Samaritans who prevented further loss of life. This is a terrible day for all Americans, but we will carry on in the American spirit, and come together with grace and strength."
On the Senate floor, Majority Leader Harry Reid held a moment of silence shortly after 5:30 p.m. And the president called on American to keep the the city of Boston in its thoughts.
"The American people will say a prayer for Boston tonight," Obama said
Vice President Biden appeared to have learned of the explosions in Boston from television.
During a call with gun control activists Monday afternoon unrelated to the incident, Biden said, "As I am speaking here, they just turned on the television in my office and apparently there has been a bombing - I don't know any of the details of what caused it, who did it."
Biden added, "Our prayers are with the people in Boston who have suffered injury. And I don't know how many of them there are."
Not long after the explosions in Boston, authorities in Washington closed off an area near the White House to pedestrian traffic.
"Out of an abundance of caution, we have expanded our security perimeter at the White House complex," said U.S. Secret Service spokesman Edwin Donovan. "It is not unusual to expand or contract these security perimeters."
Washington Mayor Vincent Gray also said that commuters would see a stepped-up presence of police on Monday night.
Politicians from New England and throughout the country responded with a mixture of heartbreak and outrage.
"Our thoughts and prayers are with the victims and our heartfelt thanks go out to those first responders, medical personnel, volunteers, and citizens who were on the scene to help those in need," said Sen. Jack Reed, D-R.I., "I have faith that law enforcement will get to the bottom of this and hold whoever is responsible accountable to the fullest extent."
"Our hearts are heavy with the news out of Boston today. #PrayforBoston," tweeted the 2012 GOP presidential nominee and former Massachusetts Gov. Mitt Romney.
"Heartbreaking day for Boston. Praying for everyone back home as this terrible tragedy unfolds," tweeted Rep. Joe Kennedy, D-Mass.
In another tweet, Rep. Eric Swalwell, D-Calif., said he was praying "for those murdered."
Rep. Ed Markey, D-Mass., who is making a run for the Senate seat in Massachusetts left vacant by Secretary of State John Kerry, announced he has suspended campaign activities including canvassing, phone banking, fundraising and television advertisements.