Iran policeman killed amid unrest in southeast
The violence began earlier this week when a clash involving fuel smugglers at the Pakistani border triggered attacks on government buildings in the nearby city of Saravan, 270 kilometres (170 miles) southeast of Zahedan, in which at least one person was fatally wounded.
Sistan-Baluchistan has a large ethnic Baluch population, that straddles the border and mainly follows the Sunni branch of Islam, not the Shiite branch followed by most Iranians.
The province has long been a flashpoint for cross-border attacks by separatists and Sunni extremists.
Zahedan county governor Abouzarmahdi Nakahei said the latest violence was fuelled by "fake" reports of deaths in the unrest in Saravan.
"Following the propaganda and rumours by foreign media, criminal elements attacked Kurin police station in Zahedan with light weapons and grenade launchers," Nakahei told state news agency IRNA, without saying when the attack took place.
He said the assailants had acted on the "excuse of showing solidarity for the fake deaths at Saravan's Shamsar police station."
Police returned fire and the attackers eventually fled, but one officer was killed in the firefight, Nakahei said.
Read more: Is Iran's nuclear deal still viable?
Provincial deputy governor Mohammad-Hadi Marashi said several people had been wounded, one of them fatally, when officers at the Shamsar police station opened fire on a crowd on Monday.
He said the crowd had attacked the police station after an incident at the border in which Pakistani soldiers opened fire on fuel smugglers attempting to cross into Iran, killing one person and wounding four.
On Tuesday, angry protesters attacked the county governor's office in Saravan, damaging property before being dispersed, Marashi said.
Provincial police chief Ahmad Taheri told the Tasnim news agency that hundreds had taken part in the Tuesday attack but the situation was now "under control".