"The United States condemns today's attack in the Woolwich district of London. We stand with our UK allies in the face of such senseless violence," State Department spokesman Patrick Ventrell said yesterday.
"Our thoughts and condolence are with the family of the victim and the British people," Ventrell said in a statement.
The British Government is considering this as a terrorist attack.
Television footage showed one of the men with a bloodied meat cleaver making political statements.