Saudi Arabia hosts a summit of Arab Gulf leaders yesterday as crises brew over a bitter diplomatic dispute with Qatar, the war in Yemen and the murder of Saudi journalist Jamal Khashoggi.

Qatari Emir Sheikh Tamim bin Hamad al-Thani has been invited by Riyadh, which severed diplomatic ties with Doha in 2017 along with Bahrain and the United Arab Emirates, to the Gulf Cooperation Council talks.

But it was unclear if the emir would attend the annual gathering of the GCC, whose others members—Kuwait and Oman—have stayed out of the worst political fallout between the energy-rich Gulf powers.

Saudi Arabia and its allies accuse Qatar of supporting terrorism and fostering close ties with their regional rival Iran.

Doha—which announced this month it was quitting the Saudi-dominated OPEC oil cartel—denies the allegations, but the dispute has dragged on. “Qatar has burned all the bridges enabling it to take back” its place within the GCC, Bahraini Foreign Minister Sheikh Khaled bin Ahmad Al-Khalifa said in the run-up to the summit.

The GCC was formed in 1981 at the height of the Iraq-Iran war and two years after the Islamic revolution in Tehran sparked concern in Sunni-led Gulf states, many of which have sizable Shiite populations, including in Bahrain. GCC secretary general Abdellatif al-Zayani has said the 39th summit in Riyadh would review ties with Iran after the US reimposed an oil embargo and other sanctions on Tehran.

The US administration, which pulled out from a landmark 2015 nuclear deal between Tehran and major world powers in May, has vowed to reduce Iran’s oil sales to zero.

Saudi Arabia, along with allies UAE and Bahrain, accuses Tehran of fomenting unrest among Shiites in the Gulf, and has backed the US in piling pressure on Iran.

This contrasts with Kuwait and Oman which prefer normalising ties with the Islamic republic. Kuwait has also been mediating between its Gulf partners and Qatar.

Sunday’s summit also comes as delegations from the Saudi-backed Yemeni government and Iran-linked Shiite rebels hold UN-brokered peace talks in Sweden.

Yemen’s capital has been held since 2014 by Huthi rebels who drove the government out and seized a string of ports.

The Yemeni government, based in the southern port city of Aden, has fought to drive back the rebels with support from a military coalition led by Riyadh and the UAE.