Obama also told Mayor Tom Menino and Gov. Deval Patrick that his administration would provide whatever support was needed in responding to the incident, the White House said.

The president was briefed on the explosions by Homeland Security adviser Lisa Monaco shortly after 3p.m. EDT.

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.

“Apparently there has been a bombing,” Biden said. “I don’t know any of the details of what caused it, who did it. I don’t think it exists yet. But our prayers are with those people in Boston who suffered injury.”

Shortly after the explosions, 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.