Iran shelled Kurdish rebel positions in a remote area of northern Iraq's largely autonomous Kurdistan region on Saturday, a spokesman for the Kurdish Peshmerga border guards said.
"They fired shells at the mountain area of Choma Sar. There were no casualties because it is a mostly unpopulated area," Jabbar Yawar said. The shelling started at around 8:30 a.m. (0530 GMT) and continued for more than an hour.
Border guards also spotted Iranian military helicopters bombing an area just inside Iran. The aircraft did not cross into Iraq, he said.
Iranian officials did not immediately comment.
The shelling followed clashes between Iranian police and guerrillas from the Party of Free Life of Kurdistan (PJAK), an offshoot of the Kurdistan Workers Party (PKK) which took up arms in 1984 for an ethnic homeland in southeast Turkey.
Gunmen killed 10 Iranian police in that firefight in western Iran on April 25. Ten PJAK fighters were also killed, Iranian state media said.
"According to our reports, these strikes came as a retaliation for an attack by the PJAK fighters on Iranian security forces ... inside Iranian territories," Yawar said.