Ilya Yashin was one of several opposition leaders detained during a sanctioned December 31 rally that marked Russians' constitutional right to gather in public places. He was sentenced to five days in jail.

A senior member of the Solidarity opposition movement, Yashin appealed his conviction and a Moscow court heard testimony from the arresting officer last week, the opposition Novaya Gazeta newspaper reported.

During the hearing, Yashin questioned the policeman as to why some of his court testimony appeared to contradict what he had written in his police report.

At a certain point, the policeman told the court: "There was an order to prepare this report... Under dictation," the newspaper said.

When Yashin asked the policeman whom the order had come from, the latter identified a senior lieutenant in charge of personnel.

"At that point, he was our commander," said the policeman, who was identified as Artyom Charukhin.

The New Year's Eve demonstration was sanctioned but still resulted in a series of arrests after the police moved against those trying to extend their rally beyond the small space assigned to them on a central Moscow square.

Those arrested and jailed also included former first deputy prime minister turned opposition leader Boris Nemtsov, who has been mooted as a potential contender in the next presidential elections scheduled for 2012.

The US State Department has expressed "regret" over the incident.

Another hearing into Yashin's appeal has been scheduled for Thursday, Novaya Gazeta said.