Tusk summoned again to Polish court

It is the second time that the prosecutor - who is directly controlled by Poland's Law and Justice government - has asked Tusk to appear before the court.

On 20 April, Tusk was quizzed for eight hours on a cooperation accord between Polish military counter-intelligence and Russia’s FSB spy service, in an enquiry that accused two generals of initiating the accord without Tusk's knowledge.

This time around, Poland's military prosecutor has been charged with a breach of duties over its failure to ask Russia for permission to carry out an autopsy of the air crash victims.

Tusk's summoning, however, could be seen as part of a larger effort to discredit the European Council president.

The leader of the ruling Law and Justice party, Jaroslaw Kaczynski, severely dislikes Tusk and claims that the plane crash was a Russian plot and that Tusk was somehow involved in the killing of his twin brother Lech.

Poland's defence minister, Antoni Macierewicz, said in March that he had filed another complaint, this time accusing Tusk of “diplomatic treason” over his handling of the Smolensk investigation.

Leaving the prosecutor's office after his first visit, Tusk told journalists that if he keeps getting summoned as a witness and it starts to interfere with his work at the European Council, he will use his diplomatic immunity to reject the invitations.

The number of people who believe that the Smolensk crash was not an accident has dropped since Law and Justice came to power.

Tusk's summoning also comes amid a clash between the Law and Justice government and the EU institutions over the party’s meddling in Poland’s judicial system.

EU ministers are gathering in Brussels on Tuesday for their first official discussion on the European Commission's probe into the breaches of rule of law in Poland.