Iranian police say a double-bombing has lightly wounded three police in the southeastern city of Zahedan.

Gen. Mohammad Ghanbari, the provincial police chief, told the official IRNA news agency that the second bomb went off as police raced to the scene of the first explosion. He says the bombs were handmade and that police are investigating.

"Investigations showed that the explosion was caused by a handmade explosive device, which led to a bomb squad being dispatched to the location who found a suspicious package," said the provincial police chief, Mohammad Ghanbari.

"The second bomb detonated before being defused and lightly injured three police forces," he said, quoted by the Tasnim news agency.

Police are currently trying to identify and arrest the perpetrators.

Iranian officials said the explosions were caused by percussion grenades, and left three police officers with minor injuries.

Zahedan is the capital of Sistan-Baluchistan province, which has seen past attacks by Baluch separatists and drug traffickers.

Last month a suicide car bomber struck a police headquarters in the port city of Chabahar, also in Sistan -Baluchistan, killing at least two police and wounding 42 other people.