The United States Wednesday appealed for restraint by all parties in Ethiopia, where clashes between police and demonstrators reportedly have killed more than 20 people over two days. The State Department deplored violence by government security forces as well as what it said were cynical attempts by opposition activists to provoke violent incidents.

Officials here are faulting both sides in the renewal of violence in Ethiopia over disputed parliamentary elections in the African country last May.

Reports from the capital, Addis Ababa, say more than 20 people have been killed in confrontations between police and opposition supporters since Tuesday, and that scores of protesters including some opposition leaders have been arrested.

At a news briefing, State Department Spokesman Sean McCormack said the United States calls on all parties to show immediate restraint and step back from the climate of heightened tensions.

Mr. McCormack said the United States deplores the use of violence as well as deliberate attempts to provoke violence.

He further urged the release of all political detainees, including opposition supporters arrested in recent weeks. He said arrested opposition leaders should be treated humanely and if charged, be given just and timely trials before an impartial court.

Spokesman McCormack said opposition forces should refrain from inciting civil disobedience during the current turbulent period.  He said while peaceful protests are a legitimate democratic right, violent demonstrations threaten public safety and do nothing to advance democracy.

"Peaceful demonstrations in an effort to show opposition to a law, a political outcome, are certainly acceptable," said Mr. McCormack.  "Free expression is at the bedrock of any democracy. But deliberate and cynical attempts to provoke violence and violent reactions, and the use of violence to resolve political differences which need to be resolved in a peaceful manner, is what we're trying get at with this statement. "

Mr. McCormack said the Ethiopian government should set up an independent commission to investigate the latest incidents, as well as a similar violent outbreak last June in which dozens of demonstrators were killed.

He said the United States believes the best way forward for Ethiopia is for all political groups to take part in the democratic process, with elected members of the opposition taking their seats in parliament and assuming administration of the capital.

The opposition has refused to accept the results of the May 15 election, alleging massive fraud by the government.

According to official tallies, Prime Minister Meles Zenawi's Ethiopian People's Revolutionary Democratic Front retained control of the parliament by a small margin.

On another issue, Spokesman McCormack called on Ethiopia and neighboring Eritrea to adhere to the agreement they reached to resolve the two-year border war between them that ended in 2000.

The comments followed an expression of concern by the United Nations that the two sides have moved tanks and troops to the border area in recent weeks and might be preparing for renewed war.

As part of a peace accord ending the recent war, an independent commission with supposedly binding authority re-drew the border. But Ethiopia has refused to accept its ruling awarding a key border town, Badme, to Eritrea.

Mr. McCormack said the U.S. stand is that any differences that exist or may arise between the Horn-of-Africa neighbors need to be resolved in a peaceful manner through dialogue.