Armenian police early Saturday morning forcibly dispersed a demonstration by several hundred opposition supporters who had camped out in the capital for more than a week to protest the results of presidential elections.
The police moved in before 7 a.m. (0300GMT) and began forcing protesters onto buses. A few clashes broke out on the central Yerevan square.
The Armenian Health Ministry said 31 people, including six policemen, had sought treatment for injuries in the clash; it said 10 people were hospitalized, but did not state the severity of their injuries nor how many of them were police.
The opposition has protested the results of the Feb. 19 presidential election and tried to force a new vote. Rallies daily have drawn tens of thousands of people; a few hundred remained at the square each night in tents.
About 2,000 demonstrators marched through Yerevan on Saturday afternoon, but many downtown streets and the square that had held the camp were closed off by police. Demonstrators threw trash on some cars and pounded on a police vehicle.
The general prosecutor's office later announced it was opening a criminal investigation against the demonstrators on suspicion of holding illegal arms.
Officials say Prime Minister Serge Sarkisian _ the favored successor of outgoing President Robert Kocharian _ won the vote outright. But supporters of opposition candidate Levon Ter-Petrosian have rejected the results, alleging fraud.
The observer mission from the Organization for Security and Cooperation in Europe said there were concerns about the vote count, but it issued a generally positive assessment.
Ter-Petrosian, a former president of Armenia, appealed to the Constitutional Court on Friday to overturn the results.
Ter-Petrosian's legal status was uncertain Saturday. Security police were preventing him from leaving his residence, but he told reporters that no formal house-arrest had been announced against him.
"If he is accused of committing a crime, he should be properly charged and prosecuted in a court of law like anyone else. In a democracy you cannot arbitrarily detain political opponents," said Terry Davis, secretary-general of the Council of Europe, the continent's main human rights body.
The standoff has raised concerns of instability in the poor, landlocked country at the junction of the energy-rich Caspian Sea region and southern Europe.