The defence ministry said on Telegram it could confirm "the detention of an employee of the Kazakh military attache's office by Polish law enforcement."

Poland's ABW security service earlier said that "a citizen of one of the Asian countries established after the fall of the Soviet Union" had been detained on July 30.

"He was identified as a military intelligence officer operating under diplomatic cover in a European country," the ABW said in a statement at the time.

"He conducted intelligence activities that threatened the security of the Republic of Poland and allied military structures," it said, adding that he had been placed under arrest for three months.

Contacted by AFP, the ABW did not immediately respond on whether the man in question was the Kazakh defence ministry employee.

Kazakhstan, located in Central Asia, is a natural resource-rich former Soviet republic that became independent after the fall of the Soviet Union in 1991.