Boston Police Commissioner Ed Davis said on Monday that officials did not know of any specific threats before three devices exploded in Boston on Monday that killed at least two people.

A man in a wheelchair is taken from the scene after explosions went off at the 117th Boston Marathon in Boston, Massachusetts April 15, 2013. [Photo/Xinhua]

He said that local police is getting aid from every agency in the state and the federal government after the explosions which occurred close to the finish of the Boston Marathon.

"Every asset of the Commonwealth of Massachusetts and the federal government is either here or is coming here," Davis said. One other explosion occurred at the John F. Kennedy Presidential Library.

Speaking at a news conference at a hotel near the finish line of the Boston Marathon where two of the three explosions went off, Davis said that anything left on the streets is currently being treated as a suspicious device.