With soldiers still hunting for surviving attackers, a spokesman for the State Department said all the US ambassador's staff were accounted for.
"The United States strongly condemns the attack in Ouagadougou," spokesman John Kirby said.
"We extend our deepest condolences to the families of the victims during this senseless assault on innocent people.
"We can confirm that all chief of mission personnel are accounted for. Our embassy in Ouagadougou is making every effort to account for US citizens in the city."
At least 20 people were killed and dozens of hostages were freed during the fighting.