Turkey, Saudi Arabia and Pakistan will sign a joint defence agreement on Friday, regional sources with direct knowledge of the matter said, ​at a time of regional turmoil with Gulf states coming under ​fire from Iran after it was attacked by the US and ⁠Israel.

While the pact further cements a burgeoning grouping of major Sunni ​Muslim powers, there was no immediate clarity on each state's commitments.

A Turkish ​official confirmed the agreement will be signed.

Turkey is a member of NATO. Saudi Arabia, another US ally, is one of the world's top oil exporters and the strongest ​Gulf state, while Pakistan is the only nuclear-armed Muslim country.

Turkish President Tayyip ​Erdogan and Pakistani Prime Minister Shehbaz Sharif, accompanied by powerful army chief Asim Munir, ‌will ⁠meet Saudi Crown Prince Mohammed bin Salman in Jeddah for the signing.

The pact follows nearly a year of negotiations, reported by Reuters in January, and as the Iran war exposes Gulf states' security vulnerabilities and ​disrupts the shipping of oil ​and other ⁠key goods through the Strait of Hormuz.

Turkish Foreign Minister Hakan Fidan in January said that Ankara favoured a ​broader regional security platform to promote cooperation and stability.

An ​existing Saudi-Pakistani ⁠pact treats an attack on either as an attack on both and encompasses "all military means", a Saudi official previously told Reuters.

The Pakistani military and ⁠government did ​not immediately respond to requests for comment.

Saudi ​Arabia's government did not immediately respond to a request for comment.