PARIS (AFP) - French President Francois Hollande on Tuesday voiced "France's complete solidarity with the American authorities and people" following deadly blasts at the Boston Marathon.

In a statement, the head of state expressed "his very strong feelings following the explosions that hit the the city of Boston" and left three dead and more than 100 injured.

"In tragic circumstances, the head of state offers his condolences to the families of the victims and expresses France's complete solidarity with the American authorities and people," the statement from the Elysee said.

In another statement, the French foreign ministry said "in these difficult moments, our thoughts are with the families of the victims and injured," according to a spokesman for the Quai d'Orsay.

"We want to also assure the local and federal authorities of our support and our complete solidarity," he said. "Our consulate in Boston, our embassy in Washington, as well as all our postings in the United States are fully mobilised and at the service of our fellow countrymen."