Updated

A lawyer for Donald Tusk says the European Union leader has been summoned for questioning as a witness in a Polish investigation next week and intends to appear.

The investigation is focused on the 2010 plane crash in Russia that killed Polish President Lech Kaczynski and 95 others.

The national prosecutor's office said Thursday it wants to ask Tusk why Poland failed to ensure the correct identification of the crash victims, some of whose remains got buried in the wrong graves.

Kaczynski's twin brother, Jaroslaw Kaczynski, heads the conservative ruling party. He has accused his longtime foe Tusk, now president of the European Council, of partial responsibility for the crash and mishandling the investigation, allegations Tusk denies.

Lawyer Roman Giertych says Tusk intends to appear for the questioning next Thursday.