From the official White House Flickr page:
"President Barack Obama talks on the phone with FBI Director Robert Mueller to receive an update on the explosions that occurred in Boston, in the Oval Office, April 15, 2013. Seated with the President are Lisa Monaco, Assistant to the President for Homeland Security and Counterterrorism, and Chief of Staff Denis McDonough."
According to a Fox News article:
"President Obama is in touch with Massachusetts officials regarding the fatal explosion in Boston and has directed his administration to provide 'whatever assistance is necessary' to investigate and respond, officials told Fox News.
A White House official said the president has called Boston Mayor Tom Menino and Massachusetts Gov. Deval Patrick to 'express his concern for those who were injured and to make clear that his administration is ready to provide needed support as they respond to the incident.'"