Top European Union official Donald Tusk said Monday he had no power or role in the preparation of any flights taken by himself or Poland's president when he was prime minister.

Tusk was testifying before a three-judge panel at the provincial court in Warsaw in a case relating to the 2010 plane crash in Russia that killed President Lech Kaczynski and 95 others.

Families of some of the victims have sued officials in Tusk's government of the time, including the head of his office, saying they failed to make sure the flight would be safe. Some relative of the victims are acting as auxiliary prosecutors.

Tusk, now the president of the European Council, appeared as a witness, not a defendant. Part of the hearing was held behind closed doors.

He told the court he had no influence or role in the preparation of his or the president's flights, and had high praise for the work of the head of his office.

"It is not and should not be the task of the prime minister or the president to influence any decisions as to place of the landing, the time of the landing, the destination, the type and the choice of the plane.

"So from my point of view, it was obvious that I should not be interested and should not be influencing" flights, he said.

Supporters of Tusk on hand

Kaczynski, his wife Maria, and many state officials and military leaders were killed in the crash on April 10, 2010, near the rudimentary airport in Smolensk, Russia. They were travelling to pay homage to thousands of Polish officers killed by Soviet secret security in 1940, during World War II.

Observers say the current right-wing government in Poland is using the trial to undermine Tusk, who still has significant political potential in the country.

Jaroslaw Kaczynski, leader of the ruling Law and Justice Party, attends a ceremony in Warsaw on April 10 commemorating those lost in the crash, which included his twin brother and Lech Kaczynski's wife, Maria. (Kacper Pempel/Reuters)

The leader of the Law and Justice Party is the late president's twin brother, Jaroslaw Kaczynski. He has blamed the crash on Tusk and Russia. Official investigations have ruled the crash an accident, but Kaczynski alleges it resulted from foul play.

A group of supporters chanted "Donald, Donald" as Tusk entered the courtroom. Dozens of both supporters and opponents also stood in front of the court building.

Last year, an Appeals Court confirmed an 18-month suspended prison term for the deputy head of the Government Protection Office for irregularities in Kaczynski's flight and in a flight taken by Tusk three days earlier.