Hezbollah said it had launched dozens of rockets over the border at Kiryat Shmona in Israel in response to deadly Israeli air strikes
Three local members of the volunteer Basij militia fighting alongside the Revolutionary Guards were killed in the clashes, the statement said.
The predominantly Sunni Muslim Sistan-Baluchistan province near the Pakistani and Afghan borders has long been plagued by unrest from both drug smuggling gangs and Sunni Islamist militants fighting the country's Shia authorities.
Many of Iran’s Sunnis complain of discrimination, a charge denied by the state.
On Friday, Revolutionary Guards shot dead three men believed to have been involved in the killing of two Guards on December 25, according to Iranian media.