Six Iranian border guards were killed during clashes with an armed group in the restive southeastern province of Sistan-Baluchestan, local media reported.

The guards were killed in Saravan, near Iran's border with Pakistan, the judiciary's Mizan Online website quoted local prosecutor Mehdi Shamsabadi as saying.

Sunday's attack was carried out by "a terrorist group that was seeking to infiltrate the country" but "fled across the border after the clash", local Fars news agency reported.

The attack was one of the deadliest in the province in recent months.

On March 11, two policemen were shot dead during clashes with "criminals" in the same region, the state news agency IRNA reported at the time.