The demonstrations in Belgrade today had up to 150,000 people. They were demonstrating because Kosovo declared Independence last week and the United States supported Kosovo. The U.S embassy was broken into and set on fire.

Angry Serbs broke into the U.S. Embassy and set fire to an office Thursday night as rioters rampaged through Belgrade’s streets, putting an exclamation point of violence to a day of mass protest against Western support for an independent Kosovo.

At least 150,000 people rallied in Belgrade, waving Serbian flags and signs proclaiming “Stop USA terror,” to denounce the bid by Kosovo’s ethnic Albanian majority to create their own state out of what Serbs consider the ancient heartland of their culture.

The United States strongly criticized the violence and the Serb response. White House spokesman Dana Perino said the embassy “was attacked by thugs” and Serb police didn’t do enough to stop it. State Department spokesman Sean McCormack said the U.S. warned Serbian Prime Minister Vojislav Kostunica and Foreign Minister Vuk Jeremic that it would hold them personally responsible for further damage.

Protesters burned American flags and the mob that attacked the embassy tore down the U.S. flag there. Crowds also ransacked a McDonald’s, looted stores and fought with police in front of other diplomatic compounds in a display of the resentment seething in Serbia over the secession of what has been its southernmost province.

Here is some video with Bill Kristol, who has some great insight on these demonstrations.