China's President Xi Jinping spoke by phone with Saudi Crown Prince Mohammed bin Salman Al Saud, discussing a wide range of subjects including supporting follow-up talks between Saudi Arabia and Iran, state media CCTV reported on Tuesday.

Xi recently helped broker a surprise deal between Iran and Saudi Arabia, Middle East rivals, earlier this month to restore diplomatic ties, in a display of China's growing influence in the region which is being warily watched by the United States.

Prince Mohammed, who is also the kingdom's prime minister, voiced appreciation for China's initiative to support "efforts to develop good neighbourliness" between Sunni Muslim Saudi Arabia and Shi'ite Iran, Saudi state news agency SPA said.

The two leaders stressed the importance of strategic ties between Saudi Arabia, the world's top oil exporter, and economic powerhouse China, a main trade partner of Gulf states, it added.

Xi said the two countries will firmly support each other on issues involving their respective core interests, and make more contributions to promote peace, stability and development in the Middle East, state media reported.

Earlier this week, oil giant Saudi Aramco raised its multi-billion dollar investment in China with two deals that are the biggest to be announced since Xi visited the kingdom in December, where he attended a summit with Gulf Arab leaders.

Saudi Arabia and other Gulf states have voiced concern about perceived disengagement by main security guarantor the United States from the region and have moved to diversify partners with an eye on national economic and security interests.

The foreign ministers of Saudi Arabia and Iran are expected to meet during the ongoing Muslim holy month of Ramadan after Riyadh and Tehran agreed, following talks in Beijing, to revive relations after years of hostility that had threatened stability in the Gulf and helped fuel conflicts in the Middle East.