A charred body was found inside the US embassy in Belgrade after Serbian demonstrators set fire to the building to protest US support for Kosovo's declaration of independence.
An embassy spokesman says the body appears to be a protester who got caught in the flames. Embassy officials say all US staff have been accounted for.
The demonstrators broke away from a peaceful protest in Belgrade Thursday and attacked the embassy, setting fire to the outside of the building and one of the offices.
Protesters got inside an embassy reception area but did not enter rooms where classified material is kept.
The US State Department calls the embassy attack "intolerable," and said Serbian security was inadequate. A department spokesman Sean McCormack said authorities deployed enough police only after the embassy was breached.
Serbian Foreign Minister Vuk Jeremic told the Reuters News Agency extremists were behind the violence and called it unacceptable.
The US State Department said Serbian security forces moved against the protesters only when US Under Secretary of State Nicholas Burns telephoned Prime Minister Vojislav Kostunica. Burns warned him and Foreign Minister Jeremic that the Serbian government would be held accountable if the attack was not stopped.
The demonstrators also set fires and threw stones at the Croatian embassy, torched a guardhouse at the German mission, and burned a car outside the British embassy.
The United Nations Security Council Thursday condemned what it calls "mob attacks" on embassies in Belgrade. A council statement reminded everyone of the inviolability of diplomatic missions under a 1961 treaty. But it also welcomed Serbia's steps to restore order and protect diplomatic property and staff.
More than a dozen countries have formally recognized Kosovo's independence. Serbia has begun recalling its ambassadors from countries that support Kosovo independence.