Saudi Arabia, Turkey and Pakistan have signed a sweeping trilateral defense pact committing all three countries to treat an armed attack against one member as an attack against them all, creating a powerful new security bloc as the Middle East’s regional order rapidly shifts.

The “Mecca Joint Defence Agreement” was signed in Mecca by Saudi Crown Prince Mohammed bin Salman, Turkish President Recep Tayyip Erdoğan and Pakistani Prime Minister Shehbaz Sharif. The pact is intended to strengthen collective deterrence and expand defense cooperation among the three countries.

A Turkish official told Reuters that the agreement is defensive and not directed against any specific country. Precise obligations under the collective-defense clause have not been disclosed, but the pact could deepen cooperation in areas including military training, exercises, intelligence and defense technology. It is also open to other regional countries.

The combination is significant: Turkey possesses NATO’s second-largest military, Pakistan is a nuclear-armed state, and Saudi Arabia brings enormous financial resources and strategic influence in the Gulf. Pakistan has already deployed roughly 8,000 troops along with fighter jets, drones and an air-defense system to Saudi Arabia, Reuters previously reported.

The deal builds on the Saudi-Pakistani mutual defense agreement signed last year, which similarly declared aggression against either country an attack against both.

For Israel, Turkey’s formal entry into a broader Middle Eastern collective-defense framework will be closely watched amid severe tensions with Ankara. No Israeli response to the new agreement had been issued when Reuters published its report.