Iran foils major separatist tunnel attack in Sistan-Baluchistan region
Iran has arrested dozens of suspects accused of plotting to carry out attacks in the restive east of the country.
The men were allegedly from a Baloch militia, and aimed at targeting government forces in the east of the country where clashes between the Iranian army and separatist fighters have become more common.
Interior Minister Abdolreza Rahmani-Fazli accused the men of building 40 metre-long tunnel - 20 metres deep - to carry out attacks.
Mohammad Akbar Sharekzehi, governor of the city of Khash in Sistan-Baluchestan province, said those arrested had "intended to carry out terrorist and sabotage acts".
He said the suspects were arrested by security forces in a nearby house, where a cache of advanced military equipment were also discovered.
Earlier this month, four Iranian border guards were killed in clashes with militants in Sistan-Baluchestan province.
Last month, Iranian state news said five "terrorists" - said to be members of the Jaish al-Adl group - were killed in the Khash region.
The same month, Iran's intelligence ministry said it had thwarted a major "jihadi plot" to carry out bomb attacks in the capital Tehran and other provinces.
Jaish al-Adl is thought to be behind a number of attacks against security forces in Iran's Baloch-majority area in recent years.
Tehran has accused the group of having ties with Pakistan-based al-Qaeda cells.
Ninety percent of Iran's population is Shia Muslim, but the country has significant Sunni populations in its restive border regions, notably Kurdistan in the northeast, Sistan-Baluchestan province and Khuzestan in the southwest.
In Sistan-Baluchestan province, security forces often clash with drug traffickers and smugglers, along with separatist militants.
The province lies on a major transit route for heroin being smuggled from Afghanistan and Pakistan to Europe, the Middle East and Africa.