President Barack Obama will take a message of resolve to Boston when he travels there to speak at a vigil for the victims of Monday's explosion.
"It will be one of resolve. It will be one of the commonality that we all feel as Americans with the people of Boston and those who are visiting Boston for the marathon and who both endured this horrific event and then demonstrated their bravery in its immediate aftermath," White House spokesman Jay Carney said Wednesday.
First Lady Michelle Obama will travel with the president to Boston.
Obama continues to be briefed about the situation. Wednesday morning, he again convened a meeting in the Oval Office with his national security team on the ongoing investigation. Participants included: Attorney General Eric Holder, FBI Director Robert Mueller, Chief of Staff Denis McDonough, National Security Adviser Tom Donilon.
"The full weight of the federal government is behind this investigation, which is being led by the FBI," Carney said. "And as the president said, we will find out who did this, we will find out why, and we will bring those responsible to justice. That said, it is very important that we allow this investigation to run its full course and to ensure that we retain the integrity of that investigation."
Carney said authorities still do not know whether the explosions were caused by an organization or an individual, foreign or domestic.
"We will find out, and we will hold accountable and bring to justice whoever is responsible.
Carney asked Americans to call an 800 number, 1-800-CALL-FBI, if they have information about the attacks.