Opposition supporters clash with police during protest rally in downtown Yerevan, 1 Mar 2008

Troops and tanks are patrolling the Armenian capital, Yerevan, Sunday, after protests that left at least eight people dead and dozens injured.

President Robert Kocharian declared a 20-day state of emergency late Saturday after a day of clashes between riot police and opposition supporters who say the February 19 presidential election was rigged. Police fired tear gas and automatic weapons into the air to disperse the crowds.

After the emergency decree, witnesses said several thousand protesters remained in the streets, holding peaceful vigils. The central city appeared quiet Sunday, with television footage showing burned buildings and nearly empty streets littered with refuse and burned vehicles.

The violence began early Saturday after police tried to clear a central square where protesters have encamped since the February 19 polls.

Official results gave a landslide victory to Prime Minister Serzh Sarkisyan.

But the opposition claims its candidate, former President Levon Ter-Petrosian, won the most votes.

The U.S. State Department has called on both sides to avoid further violence and resume political dialogue.

The Organization for Security and Cooperation in Europe on Saturday condemned the Armenian government's use of force against peaceful demonstrators. Slovenia, which currently holds the European Union presidency, also voiced concern.

President-elect Sarkisyan announced plans Friday to form a coalition government with the leader of another opposition movement, the Rule of Law party.

Some information for this report was provided by AFP, AP and Reuters.