Bahrain and Saudi Arabia cut diplomatic ties with Iran on Monday, escalating a standoff that the Saudis triggered on Saturday when they executed 47 prisoners.

Among the executed was Nimr al-Nimr, a Shia cleric critical of the monarchy.

Outraged Iranians stormed the Saudi embassy in Tehran later that day.

Saudi Arabia has given Iranian diplomats 48 hours to leave the country. Neighboring Bahrain, which has a majority Shia population but is ruled by a Sunni family, has followed suit and accused Iran of “increasing, flagrant and dangerous meddling” in the internal affairs of the Gulf states.

Sudan expelled its Iranian ambassador on Monday while the United Arab Emirates recalled their ambassador to Tehran.

Americans in a bind

The crisis puts the United States in something of a diplomatic bind, writes The Wall Street Journal‘s Jay Solomon. As the oil-exporting kingdom’s most important arms supplier and ally, America would be expected to back Saudi Arabia if the conflicts escalates.

At the same time, [Barack] Obama has made the nuclear agreement with Iran, and potentially improved ties, his most important foreign policy initiative.

The same deal has alarmed American-allied Sunni states. They worry that the United States might acquiescence in Iran’s recent strategic gains in the region, including in Iraq and in Yemen, if that will stop it from developing nuclear weapons.

American leaders insists there is no such “grand bargain” with Iran, but Obama has made clear his intention to pivot away from the Middle East and toward East Asia, counting on regional powers like Saudi Arabia to take more responsibility for their own security.

Cold war

Iran and Saudi Arabia represent rival sects of Islam and find themselves on opposing sides in conflicts across the Middle East.

In Syria, Shia Iran supports the regime of President Bashar al-Assad while Saudi Arabia has armed and financed the largely Sunni uprising against him.

In Yemen, Iran has thrown its weight behind the Houthi rebels who seized much of the country last year while Saudi Arabia and its allies seek the restoration of President Abd Rabbuh Mansur al-Hadi.

Iran has also deployed its forces in Iraq at the invitation of the Shia-led government there to fight the self-declared Islamic State, a fanatical Islamist group.