Saudi Arabia, Pakistan and Turkey signed a joint defence agreement in Mecca on Friday, wedding Sunni Muslim US allies alarmed at a regional conflagration that has brought Iranian missile fire onto Gulf oil exporters. Saudi Arabia is home to Islam's holiest sites and one of the world's top oil exporters, while Pakistan is the only nuclear-armed Muslim country. Read moreMideast live: Turkey says defence pact with Saudi, Pakistan 'not aimed at any particular country'Although Pakistan agreed a mutual defence pact with Saudi Arabia last year, it has not responded to Iran's attacks on ​the kingdom militarily. Both Pakistan and Turkey have also voiced support for a maritime defence coalition Saudi Arabia has announced to protect regional shipping and energy routes. Tehran has fired on Saudi Arabia, Kuwait, Bahrain, Qatar, the United Arab Emirates, Oman, Jordan and Israel.