Obama visits French embassy after Charlie Hebdo attack

US President Barack Obama visited the French embassy in Washington on Thursday to honor the 12 victims of the Islamist attack on the satirical magazine Charlie Hebdo in Paris.

Obama, fresh from a trip to Arizona, signed a book of condolence at the embassy after Wednesday's attack in the French capital that has sparked an ongoing manhunt for two suspected gunmen.

After signing the book of condolence, Obama observed a moment of silence before shaking hands with French ambassador Gerard Araud.

"I told Presidemt Obama that we were deeply moved by the reactions of the American people, by all the expression of grief and support we received," Araud wrote on Twitter shortly after the US leader's visit.

Araud welcomed Obama's signing of the book of condolence as a "a moving and highly significant gesture."

"The French are grateful," he wrote.

Wednesday's bloody attack in Paris has triggered an outpouring of support across the United States, with many cities staging impromptu vigils for the victims.

France is America's oldest US ally, with the transatlantic partners having established diplomatic ties in 1776.