WHITE HOUSE— President Barack Obama has vowed to bring to justice to whoever was responsible for the explosions in Boston Monday that killed at least two people and wounded many others.
President Obama says he has directed the full resources of the federal government to help state and local authorities protect Americans, as an investigation continues into the Boston explosions.
"We still do not know who did this or why, and people should not jump to conclusions before we have all the facts," said Obama. "But make no mistake, we will get to the bottom of this and we will find who did this and we will find out why they did this. Any responsible individuals, any responsible groups will feel the full weight of justice."
Obama did not specifically describe the explosions in Boston as a terrorist attack. But a White House official said "any event with multiple explosive devices, as this appears to be, is clearly an act of terror, and will be approached as an act of terror.
The official said a thorough investigation will have to determine whether the Boston attack was planned and carried out by a terrorist group, foreign or domestic.
Obama said he has spoken with U.S. congressional leaders. On Capitol Hill, House Speaker John Boehner led the chamber in observing a moment of silence.
The president was notified of the explosions minutes after they occurred and briefed by his new Homeland Security adviser Lisa Monaco and other members of the White House senior staff.
Obama telephoned Boston Mayor Tom Menino and Massachusetts Governor Deval Patrick to offer support.
The president also received a briefing from Federal Bureau of Investigation Director Robert Mueller and Department of Homeland Security Secretary Janet Napolitano.
In addition to the two explosions near the Boston Marathon finish line, Boston Police Commissioner Ed Davis also reported an incendiary device and fire at the John Fitzgerald Kennedy Library. Davis said it was not certain it was related to the earlier blasts near the Boston Marathon finishing line, but officials were working on the assumption that it was.
President Obama paid tribute to the people of Boston, saying he is confident they will support each other in this difficult time.
"Boston is a tough and resilient town," he said. "So are its people. I am supremely confident that Bostonians will pull together, take care of each other and move forward as one proud city, and as they do, the American people will be with them every single step of the way."
In Washington, police cordoned off Pennsylvania Avenue in front of the White House for precautionary reasons.
In New York, a Police Department spokesman said the city increased security in the city's subway system, and around major landmarks in Manhattan, including near prominent hotels.
President Obama's Statement on the Boston Marathon Bombings