MOSCOW - Belarus has begun the next phase of its legal crackdown on protesters who were drawn to downtown Minsk in December by what they believed to be dishonest election results.

In the face of mounting criticism from the United States, the European Union and even Russia, criminal trials are being launched against about 40 defendants. At the same time, authorities have disbarred four defense lawyers, closed the office of a European watchdog agency; and warned a human rights group in Minsk that any further activity would make it liable to criminal prosecution.

"Everything is very bad," Ales Byalyatski, director of the Viasna human rights center, which got the warning, said Friday.

One defendant has already been convicted. A judge on Thursday sentenced Vasily Parfenkov, who was found to have hit a door of a government-owned building 61 times with his fist, to four years in prison.

Parfenkov had worked for a presidential candidate named Vladimir Neklyayev, one of seven candidates who were arrested after officials announced the reelection of President Alexander Lukashenko. Neklyayev was beaten unconscious at the Dec. 19, demonstration and is currently under house arrest.

Two trials are scheduled to be held Tuesday, and more are being prepared.

In Washington, Mark C. Toner, a state department spokesman, said, "The beginning of these trials is clearly another negative step on the part of the government."

Belarus came under heavy criticism at a meeting in Vienna of the Organization for Security and Cooperation in Europe, which had objected to the conduct of the December election and the treatment of the protesters. Its Minsk office has now been closed by Belarusan authorities.

"The United States calls for an end to the extensive detentions and the dismissal of all charges associated with the crackdown; a halt to the blatant harassment of civil society, independent media, lawyers and the political opposition; and the provision of space for the free expression of political views, the development of a civil society, and freedom of the media," Ian Kelly, the U.S. ambassador to the OSCE, said Thursday.

Kelly called Belarus "a country rapidly retreating from 21st century Europe and its OSCE commitments."

The two defendants facing trial on Tuesday are both Russian citizens who live in Belarus. In Moscow, the Russian foreign ministry issued a statement accusing the Belarusan interior ministry of making "rude" and "inappropriate" statements in an effort to provoke anti-Russian sentiment.

Until now Russia has largely kept quiet about the Belarusan elections and protests, but officials in Moscow apparently believe that the two Russian defendants are being used as bargaining chips by Belarus. The two countries have been sparring over an oil transit agreement that was signed late last year.

Poland, which has been taking the lead on criticism of the Lukashenko regime, said it was increasing its financial support of radio and television stations that beam news and information into Belarus.

"The Belarusan regime treats its citizens like hostages and, unfortunately, may launch new repressions against the Polish ethnic minority," Radoslaw Sikorski, the Polish foreign minister, told a Polish news web site.

At Poland's urging, the EU has banned Lukashenko and 157 other government officials from visiting any member country.

Byalyatski said he was shocked by the court proceeding on Thursday. "Four years is an awful sentence. This is too cruel."

It's evident, moreover, that the prosecutors are starting with the most minor cases, he said, and will be working their way up to the protest organizers and the opposition presidential candidates.

Belarusans aren't likely to follow the Egyptians' example, he and others said. "I wouldn't use the word revolution, because Belarusans are just calm people," Robert Tyszkiewicz, who heads a committee on Belarus in the Polish parliament, said in a recent interview.

Pay and pensions were raised just before the election, and that dampened any ardor for reform that Belarusans might have harbored, Byalyatski said. "And human rights activists alone can't change the situation in Belarus. We need masses of people."

Another difference with Egypt is the uncommonly frigid weather that has afflicted the whole country for more than a week now. Even hardy Belarusans are doing what they can to stay indoors as much as possible.