Polish former KSW MMA champion Mamed Khalidov has been arrested by anti-terrorist operatives as part of an investigation into illegally-imported stolen cars, according to reports.

Various outlets in Poland are reporting that Khalidov was apprehended in his home town of Olsztyn on Tuesday and was subsequently detained by the Anti-Terrorist Operations Office.

The arrest was ordered by the prosecutor of the Silesian Branch Department of the Department of Organized Crime and Corruption of the National Prosecutor's Office in Katowice.

Khalidov's arrest is reportedly linked with a collection of imported luxury cars that were purchased in the Czech Republic.

A statement from the National Public Prosecutor's office said: "On the orders of the prosecutor of the Silesian Branch Office of the Department for Organized Crime and Corruption of the National Prosecutor's Office in Katowice, officers detained Mamed K. on the luxury car pickup.

"In the course of the proceedings, the prosecutor of the Silesian Branch Office of the Department for Organized Crime and Corruption of the National Prosecutor's Office in Katowice determined that the vehicles were purchased in the Czech Republic. Among the luxury cars, there were such vehicles as Porsche Panamera, Range Rover Evoque, BMW M6, BMW 7 series."

It is unclear from the reports why the anti-terrorism unit was used in the operation. It may be as part of a larger anti-terrorism investigation, or it may simply be as a result of Khalidov's well-documented combat sports background.

Khalidov will appear to hear the allegations before a prosecutor takes a decision on "preventative measures."

Khalidov, 38, was born in the Chechen capital of Grozny and moved to Poland as a 17-year-old. He was eventually granted Polish citizenship in December 2010.

He began his martial arts career in 2004 and three years into his career signed with internationally-renowned Polish MMA promotion KSW.

He went on to become one of the organization's biggest stars, winning international light-heavyweight and middleweight titles before eventually announcing his retirement in December 2018 following back-to-back losses to fellow countryman Tomasz Narkun.