EU president Donald Tusk heads to Warsaw today to testify before prosecutors in an investigation into two former military counterintelligence chiefs.
The former Polish prime minister tweeted earlier this month that he would attend: "(April) 16 - holidays at home, 19 - prosecutor's office in Warsaw, 22 - my 60th (!) birthday. What a marathon. See you on the road :)"
Tusk had been summoned for the closed-door questioning in March but was unable to appear due to a previous commitment at the European Parliament.
The probe centres on Generals Janusz Nosek and Piotr Pytel who are suspected of having "overstepped their duties by collaborating with services of a foreign state" without authorisation.
According to Polish media reports, at issue is an agreement struck with Russia's FSB intelligence service -- the successor to the KGB -- shortly after a 2010 air disaster in Russia which killed then Polish president Lech Kaczynski and scores of senior Polish statesmen.
Tusk was prime minister at the time.
Some reports suggest the agreement was aimed at cooperating on the withdrawal of Polish troops from NATO operations in Afghanistan at the time, while others say it allowed FSB agents to visit Polish SKW military counterintelligence headquarters unfettered.
The original summons came days after EU leaders gave Donald Tusk another term as president despite strong opposition from Poland.
An angry Warsaw accused the EU of "cheating".
Jaroslaw Kaczynski, the powerful head of Poland's governing rightwing Law and Justice (PiS) party, has accused political arch-rival Tusk of "moral responsibility" for the death of his brother Lech in the air crash in Russia.
Before boarding his train to Warsaw today, Tusk told reporters that regarding the day's questioning "I have no doubt that this is part of a political witch-hunt."
Tusk's supporters said they would greet him when he arrives, writing on Facebook: "Varsovians, let's show Donald Tusk our support and let's welcome him at the train station.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)