WARSAW, December 15. /TASS/. The incident that injured a Polish police commander could have been caused by a grenade launcher round, Radio ZET reported Thursday, citing its sources.

According to the radio station, the explosion could have been caused by a grenade launcher round with training payload.

The factuality of the explosion was later confirmed by the Polish Ministry of the Interior. According to the Ministry, the exploded package contained a gift that the police commander received during his visit to Ukraine on December 11-12 from a head of a Ukrainian security agency. This present could potentially have been a grenade launcher.

The incident caused minor injuries to the commander and a civilian police employee.

The Polish side contacted Kiev requesting an "appropriate explanation." The incident is being investigated by Polish security agencies and prosecutors.