Tensions sparked by cleric’s execution raise alarm about growing hostilities in regional battle for influence between two countries

Saudi Arabia cut diplomatic relations with Iran as tensions between the two long-time regional rivals reached new heights amid concern what it could mean for the fight against ISIS, as well as other conflicts in the Middle East region.

Saudi Arabia announced on Sunday that Iranian diplomats had 48 hours to leave the kingdom shortly after Iran’s top leader harshly criticized the execution of Shiite cleric Sheikh Nimr al-Nimr. The Saudi Foreign Ministry said its diplomatic staff was already being evacuated from Iran. The move was surprising because after protesters stormed the Saudi Embassy in Tehran, the Iranian government appeared to be trying to quell tensions.

Saudi Foreign Minister Adel al-Jubeir told a news conference in Riyadh that the envoys of Iran had been asked to quit Saudi Arabia within 48 hours. The kingdom, he said, would not allow the Islamic republic to undermine its security.

Tension escalated between Saudi Arabia and Iran over Riyadh’s execution of a prominent cleric. The cleric, Sheikh Nimr al-Nimr, was among 47 men executed in Saudi Arabia on terrorism-related charges, drawing condemnation from Iran and its allies in the region, and sparking fears that sectarian tensions could rise across the Middle East.

Western governments quickly became concerned the abrupt escalation of tensions foreshadow “a new year of growing hostilities in the regional battle for influence between the Sunni kingdom of Saudi Arabia and Iran, the dominant Shiite power in the Middle East,” notes the Wall Street Journal. The severing of diplomatic ties comes at a particularly bad time considering that the United States and other Western countries were “hoping that even limited cooperation between the two powers could help end the crushing civil wars in Syria and Yemen and ease tensions in Iraq, Bahrain, Lebanon and elsewhere,” points out the New York Times.

Although the U.S. State Department publicly called for calm, White House officials were privately critical of Saudi Arabia for moving forward with the execution that they knew would spark regional upheaval. “This is a dangerous game they are playing,” a U.S. official tells the Washington Post. “There are larger repercussions than just the reaction to these executions,” the official added, noting the fight against ISIS as an example. The State Department had reportedly been warning Riyadh for months about the potential for regional strife if it went ahead with the executions.