Saudi Arabia defied the world by escalating its crisis with Iran over the execution of a prominent Shia cleric, severing commercial ties and air links with the Islamic Republic amid a wave of retaliatory attacks.

Adel al-Jubeir, the Saudi Foreign Minister, called for Iran to "act like a normal country" as he announced that all flights to the country would stop and all Saudi citizens banned from travelling there. Saudi Arabia's Arab allies, including Bahrain and Sudan, the latter once an ally of Tehran, announced they were withdrawing their ambassadors.

But there were signs of an international backlash against Riyadh's hardline position, which it justified as a response to Iranian vows of vengeance for the death of the cleric, Sheikh Nimr al-Nimr, and the storming by a mob of the Saudi Embassy in Tehran.

British Prime Minister David Cameron said he "condemned the death penalty" and had raised the case with Riyadh. He said the row was "hugely concerning" for regional stability.


The White House said that US officials had warned Saudi Arabia that executing al-Nimr would have "damaging consequences".

"Unfortunately the concerns that we raised with the Saudis have precipitated that kind of consequences we were concerned about," said Josh Earnest, spokesman for President Barack Obama. Earnest called on both Iran and Saudi Arabia to "show some restraint" so as to not further "inflame" the situation.

Germany went further. Its Economy Minister, Sigmar Gabriel, said it would reconsider its weapons exports to the country, one of the world's biggest spenders on the international arms market. "We can see that it was right to neither deliver tanks nor G36 assault rifles to Saudi Arabia," he said, referring to previous declined requests for arms transfers. "Now we have to review whether we also need to evaluate defensive armaments more critically in the future."

In signs of escalation on the ground, a man was shot dead and a child injured as protesters in Nimr's home town, Awamiya in Qateef province, clashed with police. Security officials in in Iraq said uniformed men had detonated explosives outside Sunni mosques in the Shia-majority Hilla region, south of Baghdad, under cover of darkness.