The International Helsinki Federation, a human rights body that advises the United Nations, said harsh treatment of anti-government protesters in Armenia is a violation of political and human rights and that international experts should investigate the abuses.

The Vienna-based International Helsinki Federation for Human Rights (IHF) accused authorities in Armenia of using violence against demonstrators, and called for the end of what it says is the authoritarian rule of President Robert Kocharian.

Demonstrations against the Kocharian government have occurred almost daily since the beginning of the month.

The IHF says police used water cannons to break up a rally Tuesday near the presidential palace in the capital, Yerevan.

President Kocharian insisted the measures were necessary to combat political extremists who he said were threatening the constitutional order.

However, IHF Director Aaron Rhodes says the oppression is likely to lead to more confrontation and instability. "What they [the authorities] are doing by disallowing these demonstrations, they are really perpetuating disorder," he said. "There are many reports of police brutality, and including brutality to journalists and a number of people have been beaten in the context of these demonstrations and have wound up in hospital."

Mr. Rhodes added that some journalists had their cameras smashed and cell phones were disconnected. He also said that copies of a Russian daily newspaper covering the demonstrations were stopped at the border and that some television stations were unable to transmit for a time.

Police were reported to have raided opposition offices, smashing computers and detaining activists.

Mr. Rhodes called for an independent investigation into such incidents with experts from the Organization for Security and Cooperation in Europe (OSCE), of which Armenia is a member. The OSCE has criticized recent Armenian presidential and parliamentary elections, saying they were flawed.

The State Department has said it is concerned over the sharp escalation in confrontation between the government and its opponents in the Caucasus republic, once part of the Soviet Union.