Bahrain and Sudan join Saudi Arabia in ceasing diplomatic ties with Iran

•  UAE also downgraded relations with Tehran

Demonstrators protest at beheading of Sheikh Baqir Al Nimr and companions in Saudi Arabia. Photograph: Azam Husain/Barcroft India

Saudi Arabia’s closest Sunni allies have followed its lead and severed or downgraded their relations with Iran, as the repercussions continued over the execution of a leading Shia cleric by the Saudi authorities, which has provoked international condemnation.

Ban Ki-moon, the UN secretary general, called the dramatic rupture between Riyadh and Tehran “deeply worrying,” a spokesman said.

Bahrain and Sudan both cut their ties with Iran, while the United Arab Emirates downgraded its relations in a bitter row that has highlighted escalating Sunni-Shia tensions and cast a long shadow over efforts to end the wars in Syria and Yemen.

The swift succession of punitive diplomatic moves followed attacks by Iranian crowds on the Saudi missions in Tehran and Mashhad in protest at the execution of Sheikh Nimr al-Nimr on Saturday. Three other Saudi Shias were executed, as were 43 Sunnis convicted of terrorism. It was the biggest mass execution in the conservative kingdom since 1980.

Iran hailed Nimr as a “martyr” and warned Saudi Arabia of “divine revenge”. But the attacks on Saudi missions were also condemned inside Iran as an own goal that had diverted attention from the executions.

Adel al-Jubeir, the Saudi foreign minister, blamed the row on Iran’s “aggressive policies” and said Riyadh would halt air traffic and commercial relations with Iran. He said Iranians would, however, still be able to visit the kingdom for pilgrimages to Mecca.

The UN secretary general spoke to both Jubeir and Iran’s foreign minister, Mohammad Javad Zarif, and urged them “to avoid any actions that could further exacerbate the situation between two countries and in the region as a whole”.

Bahrain, which blames Iran for fomenting subversion and terrorism among the island state’s restive Shia majority, attacked Tehran for its “blatant and dangerous interference” in Gulf affairs. Sudan followed suit shortly afterwards, amid speculation that other north African states might do the same.

The UAE downgraded its diplomatic representation to Iran, replacing its ambassador with a chargé d’affaires. The relatively modest step reflects the close trade ties between the two countries despite longstanding political tensions.

Late on Sunday, a man was shot dead in Saudi Arabia’s Eastern province, while two Sunni mosques in Iraq’s Shia-majority Hilla province were bombed in the fallout.

THE GUARDIAN