WASHINGTON (AP) -- With little official information to guide them, members of Congress strongly suggested on Monday that the deadly Boston Marathon explosions were acts of terrorism and vowed to bring anyone responsible to justice. "My understanding is that it's a terrorist incident," said Sen. Dianne Feinstein, a California Democrat who chairs the Senate Intelligence Committee. She told reporters she had been in contact with U.S. intelligence agencies and they reported no advance warning that "there was an attack on the way." Two other members of the panel, Sens. Susan Collins, R-Maine, and Angus King, I-Maine, said that based on initial press reports that "multiple improvised explosive devices may have been involved at this high profile national event bear the hallmarks of a terrorist attack." The remarks made by the three lawmakers stood in contrast to President Barack Obama's own brief statement at the White House, where he made no mention of terrorists or terrorism as a possible cause of the bombings. Majority Leader Harry Reid said on the Senate floor that Obama had spoken with officials in Massachusetts and "pledged every federal resource available ...to bring justice to the perpetrators ..." House Democratic Leader Nancy Pelosi said "we will ensure that justice will be done" as the casualty toll mounted in explosions blamed for at least two deaths and dozens of injuries. Lawmakers in both houses marked the bombings with moments of silence. Reid led the Senate in a brief pause, and officials said Speaker John Boehner intended to do the same when the House convened later Monday. In a written statement, Boehner said: "This is a terrible day for all Americans, but we will carry on in the American spirit, and come together with grace and strength."