Iran's official news agency is reporting that a policeman died and two of his colleagues were wounded when an attacker on a motorcycle threw an explosive device at their car.

IRNA reported on Thursday that the attack happened earlier this week, on Tuesday night, in the country's Kurdish region, in the predominantly Kurdish town of Marivan near the border with Iraq.

Sporadic clashes between Iranian forces and Kurdish separatists have left casualties on both sides in recent months.

Earlier in August and after a years-long trial, Iran executed 20 Kurdish suspects who were convicted of terrorist activities. The execution prompted an international outcry. Iran dismissed the criticism as meddling in its internal affairs.