On January 4, Bahrain and Sudan joined Saudi Arabia in severing ties with Iran amidst escalating tensions between Tehran and the Sunni states set off by the execution of a Shiite clerk in Saudi Arabia over the weekend.

The execution came after an attack on the Saudi embassy in Tehran, leading to Riyadh severing ties.

The United Arab Emirates also said that it had summoned back its ambassador from Iran on January 4 and downgraded diplomatic relations with Tehran over its “interference” in the affairs of Gulf and Arab countries.

The UAE decided to lower “diplomatic representation to the level of charge d’affaires and reduce the number of Iranian diplomats in the country,” the foreign ministry said in a statement, quoted by the official WAM news agency.

This move came after Saudi Arabia ended ties with the Islamic Republic on January 3.

“This exceptional step has been taken in the light of Iran’s continuous interference in the internal affairs of Gulf and Arab states, which has reached unprecedented levels,” said the UAE foreign ministry.

The UAE said that relations should be based upon “mutual respect for the sovereignty” and “non-interference in the internal affairs of others.”

The UAE benefits from strong business ties with Iran, and the emirate of Dubai is home to a large Iranian community.

Saudi Foreign Minister Adel al-Jubeir announced on January 3 that Saudi Arabia was ending diplomatic relations with Iran after protesters stormed and set fire to its embassy in Tehran to protest Riyadh’s execution of a Shiite clerk, Sheikh Nimr al-Nimr.

Sheikh Nimr was a vocal critic of Saudi Arabia’s Sunni monarchy but had denied ever calling for violence. His execution led to outrage among Shiites all over the region.

Jubeir also said that all Iranian diplomats had to leave Saudi Arabia within 48 hours.

Saudi Arabia “is breaking off diplomatic ties with Iran and requests that all members of the Iranian diplomatic mission leave… within 48 hours,” he told a news conference.

On January 3, Iran’s Supreme Leader warned that Saudi Arabia would face “divine revenge” for executing a Shiite clerk, as criticism came in from Iraq and demonstrators took to the streets.

Since King Salman ascended to the throne a year ago, executions have risen significantly in Saudi Arabia, with 153 put to death in 2015, which is nearly twice as many as in 2014, for crimes that range from murder to drug trafficking, armed robbery, rape, and apostasy.

Human Rights Watch said that the January 2 “mass execution was the largest since 1980” when 68 militants who had captured Mecca’s Grand Mosque were beheaded.

“Saudi Arabia had a shameful start to 2016, executing 47 people in a day, after a year with one of the highest execution rates in its recent history,” said HRW’s Middle East director Sarah Leah Whitson.

According to Amnesty International, Saudi Arabia was using Nimr’s execution “to settle political scores.”

The United Nations, the United States, and the European Union have all criticized the executions, which the Saudis carried out against people it claimed were guilty of terrorism-related charges.