“Three policemen were martyred in a terrorist attack on a police patrol,” reports the Iranian state news agency IRNA, according to AFP.
A fourth police officer later died of his injuries, according to the country’s state television.
The circumstances surrounding the attack were not immediately clear.
The province, which also borders Afghanistan and Pakistan, has been plagued by unrest involving drug-trafficking gangs, insurgents from the Baloch minority and Sunni Muslim extremist groups.
Earlier in May, five Iranian border guards were killed in clashes with an armed group in Saravan, southeast of the provincial capital Zahedan.