A Polish security official says Poland has expelled a Russian historian on suspicion that he acted against Poland's interests.

A spokesman for the minister in charge of state security, Stanislaw Zaryn, said Friday the man used his contacts among Polish historians and journalists to promote Russia's viewpoint, to discredit Polish authorities and to undermine Poland's ties with Ukraine.

The man, identified only as Dmitry K. in line with Poland's privacy law, taught at a college in Pultusk, eastern Poland. He was expelled Wednesday.

Zaryn said he had failed to tell the college about his cooperation with the Russian Institute for Strategic Studies, which is led by a former foreign intelligence service chief and advises the Russian government.

Poland, a NATO member, is distrustful of Moscow's activity in the region.