Islamabad, March 21, 2019 (AFP) -

The Pakistan military said in a statement on Thursday that it had rescued four Iranian soldiers being held captive by a militant group in the country's restive southwest.

The rescue took place in Chaghi district of Balochistan province, near the Afghan border, the statement said.

"Terrorists of a proscribed organization were reported to have entered Pakistan from Afghanistan side along with abducted Iranian soldiers," it said.

"After exchange of fire, four Iranian soldiers (were) recovered," it continued.

The statement said the soldiers were being handed over to Iranian authorities, though it did not say when. It also did not say what date the rescue took place, or name the group holding the soldiers.

Iran's Foreign Ministry spokesman Bahram Ghasemi expressed Tehran's gratefulness for the rescue of the soldiers in an official statement issued on Thursday.

"We express our thankfulness and appreciation to the Pakistan government and army for the successful operation that freed these brave border guards," said the statement, published on the official website of Iran's Ministry of Foreign Affairs.

Ghasemi further expressed hope that the remaining border guards will be freed and returned to Iran as soon as possible.

The incident comes months after the Sunni jihadist group Jaish al-Adl abducted 12 Iranian security personnel in October last year near the border.

Five of them were later released and handed back to Iran by Islamabad.

Relations between Pakistan and Iran recently suffered another blow after Tehran said a Pakistani suicide bomber was behind a February 13 attack that killed 27 Revolutionary Guards in its volatile southeastern province of Sistan-Baluchistan.

Jaish al-Adl, which Tehran says operates mostly out of bases in Pakistan, claimed responsibility for the blast.