Updated

Polish police said Sunday that they are filing charges against dozens of people, including a prominent democracy activist from the Solidarity era, for obstructing a memorial observance for the late President Lech Kaczynski, who died in a plane crash in Russia seven years ago.

The crash occurred April 10, 2010, and on the 10th of every month Kaczynski's surviving twin brother Jaroslaw Kaczynski, chairman of the conservative ruling party, leads a memorial observance in Warsaw in honor of his brother and the 95 others who died with him.

Protesters tried to block the observance Saturday evening, with some chaining themselves together on a street, and were removed by police.

Warsaw police said they were charging Wladyslaw Frasyniuk, a prominent member of Solidarity in the 1980s, with violating the bodily integrity of a police officer, a crime that carries a sentence of up to three years. In all, police asked courts to charge 91 protesters.

"Wladyslaw Frasyniuk used his physical strength against a policeman and blocked a legal gathering," the Interior Ministry said. "He was not detained. He was responsible for the violation of the integrity of an officer on the job. In Poland, everyone is equal before the law."

Frasyniuk disputed the ministry's claim, saying he never attacked an officer and only tried to defend himself.

"There was definitely no aggression from my side," Frasyniuk told The Associated Press. "Our gathering was lawful and in line with the constitution and it was the police officers who violated the law."

"We have the right to show our anxiety with what is happening in Poland," he added.

The monthly observance has become a flashpoint between Kaczynski and his supporters, who insist they are observing a religious memorial for the dead, and his opponents, who accuse him of using the memorial for political purposes. They more broadly object to the political direction under Kaczynski's party, which the European Union accuses of rule-of-law violations.

Kaczynski delivers a short speech each month in which he denounces those whom he accuses of trying to harm Poland, including Russia, which he has blamed for the crash, and his domestic political opponents. Polish and Russian investigations have found it to be an accident.

Barbora Cernusakova, one of about a dozen Amnesty International monitors present Saturday evening, told The Associated Press that she witnessed police issuing a warning before removing the protesters and holding dozens of them for about an hour on two sites a bit away from the assembly.

She said they didn't use excessive force, but that police didn't allow a lawyer access to the protesters. She also said Amnesty International is concerned about the high number of protesters being charged.