Updated

Top European Union official Donald Tusk says his appearance in court in a case relating to the 2010 plane crash that killed Poland's president and 95 others is about "important matters."

Families of some of the victims have sued officials in the government of the time, saying they failed to make sure the flight would be safe. Tusk, who is appearing as a witness, not a defendant, was Poland's prime minister at the time of the crash.

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

Tusk was traveling by car Monday from his northern hometown of Sopot to Warsaw to appear before the Provincial Court.

Leaving home, he said his appearance was "not about (my) mood but about important matters."