ANDREWS AIR FORCE BASE, Maryland (Reuters) - U.S. President Barack Obama vowed on Friday that the United States will do everything possible to protect Americans overseas, and underscored that host countries must provide security for diplomatic missions.

"We will continue to do everything in our power to protect Americans serving overseas, whether that means increasing security at our diplomatic posts, working with host countries - which have an obligation to provide security - and making it clear that justice will come to those who harm Americans," Obama said.

He spoke at a ceremony honoring the return of the bodies of U.S. Ambassador Christopher Stevens, State Department information management officer Sean Smith and security personnel Tyrone Woods and Glen Doherty, both former Navy SEALS, who died in the assault on Tuesday on the U.S. Consulate in Benghazi, Libya.

(Reporting By Patricia Zengerle; Editing by Doina Chiacu)