"The terrorist group Jaish al-Adl (Army of Justice in Arabic) has posted two photos... claiming that those in it are the forces abducted" on October 16, ISNA said.

Jaish al-Adl, formed in 2012, is a successor to the Sunni extremist group Jundallah (Soldiers of God) which has carried out a spate of attacks on Iranian security forces in recent years in the southeastern province of Sistan-Baluchistan.

The photos show seven members of the elite Revolutionary Guards force and five police commandos, all in combat gear, according to state news agency IRNA.

The Iranians, including intelligence offices, were abducted near Lulakdan, a village 150 kilometres (90 miles) southeast of Zahedan, capital of Sistan-Baluchistan.

They were "made unconscious" by a "single infiltrator" and then kidnapped and taken to bases inside Pakistan, said Guards commander Major General Mohammad Ali Jafari, quoted by IRNA.

The photos also show a haul of automatic weapons and sniper rifles, rocket launchers, machine-guns, grenades and ammunition, apparently seized from the Iranian forces.

Sistan-Baluchistan has long been a flashpoint, with Pakistan-based Baluchi separatists and jihadists carrying out regular cross-border raids against Iran.

The province has a large, mainly Sunni Muslim ethnic Baluchi community which straddles the border.

A delegation led by the Guards' ground forces commander Mohammad Pakpour visited Pakistan on Monday to follow up on efforts to free the Iranians, the force said on its website.

Pakistan said last Wednesday that it has launched "active" efforts to locate the missing men.

Pakistani Foreign Minister Shah Mahmood Qureshi has blamed the kidnapping on "our common enemies unhappy with the existing close, friendly relations between Pakistan and Iran".