"If the security of the Gulf is directly threatened, Egypt will mobilise its forces to support its brothers," Sisi was quoted as saying in a meeting with the press in the Red Sea resort of Sharm el-Sheikh.

"Egypt stands body and soul by the side of our Gulf brothers," he said, without specifying the source of any outside threat.

Saudi Arabia and the United Arab Emirates have pumped billions of dollars into Egypt's economy since its military -- then headed by Sisi -- toppled Islamist president Mohamed Morsi in 2013.

Sisi successfully ran for Egypt's presidency in 2014 and has cracked down on opposition, including Morsi's Muslim Brotherhood. He was re-elected with 97 percent of the vote in elections in March this year.

Along with the UAE, Bahrain and Saudi Arabia, Egypt severed diplomatic and economic relations with Qatar in June 2017, accusing it of links to extremist groups and being too close to Iran -- charges Doha denies.

Shiite powerhouse Iran is Saudi Arabia's main regional rival.

Egypt is also a member of the Saudi-led coalition which has since 2015 been fighting the Iran-backed Huthi rebels in Yemen.