Saudi Arabia is severing its diplomatic ties with Iran, foreign minister Adel bin Ahmed Al-Jubeir has announced in a televised news conference.

The breakdown in relations is the culmination of a conflict caused by Saudi Arabia's execution of Sheikh Nimr al-Nimr, an Shia cleric and prominent critic of the Saudi Arabian government, and the storming of the Saudi embassy in Iran that resulted.

All Iranian diplomats now have 48 hours to leave the conservative kingdom, beginning a period which marks a new low in relations between the two major Middle Eastern powers.

The cutting of ties followed a long period of conflict between the opposed countries over al-Nimr's treatment. Iran's supreme leader, Ayatoallah Ali Khameni, predicted "divine vengeance" would fall on Saudi Arabia after al-Nimr's execution, and there were anti-Saudi protests as far afield as Pakistan over his death.

Following the execution, protesters stormed the Saudi Embassy in Tehran, ransacking and setting fire to the property before being pushed back by police.

Iranian president Hassan Rouhani attempted to calm the conflict with Saudi Arabia by calling for the perpetrators of the embassy attack to be identified and captured, but Saudi Arabia was not turned.

Al-Nimr was killed along with 46 other accused terrorists, in a mass execution that took place behind closed doors.

He was a constant critic of the Saudi and Bahraini royal families, and was popular amongst Saudi Arabia's Shia minority. Despite calls for clemency from Iran and the United Nations, Saudi Arabia claimed he was attempting to stir up dissent in the country through his calls for the introduction of democracy and elections.