Arab leaders were due to meet at the eastern Saudi city of Dahran Sunday, 24 hours after the US, France and Britain launched missile strikes on Syria’s chemical sites. Saudi Arabia and Qatar, though rivals, both voiced support for the US-led action. Hanging over the meeting are rising tensions between Riyadh and Tehran. King Salman is to open the 22-member Arab League session with a three-point agenda: Iran, Syria and US President Donald Trump’s Jerusalem policy. Its members are waiting to see whether the Qatari emir Tamim al Thani will take his seat, as a test of whether President Trump succeeded in his bid to mediate the quarrel between Riyadh and Doha when he received the emir at the White House last week. The Saudis and United Emirates accuse the Qatari ruler of supporting extremist Islamist terrorists and close ties with Tehran.