Saudi Arabia says it has broken off diplomatic ties with Iran, amid a row over the Saudi execution of a prominent Shia Muslim cleric.
Saudi Foreign Minister Adel al-Jubeir was speaking after demonstrators stormed the Saudi embassy in Tehran.
Sheikh Nimr al-Nimr and 46 others were executed on Saturday after being convicted of terror-related offences.
But his supporters say the execution of Al-Nimr, a vocal supporter of anti-government protests, was politically motivated.
All Iranian diplomats have been recalled from Tehran and must leave Saudi Arabia within 48 hours, Mr Jubeir said.
Saudi Arabia would not let Iran undermine its security, accusing it of having "distributed weapons and planted terrorist cells in the region", he said.
"Iran's history is full of negative interference and hostility in Arab issues, and it is always accompanied by destruction."
US state department spokesman John Kirby said: "We will continue to urge leaders across the region to take affirmative steps to calm tensions".
"We believe that diplomatic engagement and direct conversations remain essential," he said.
NZ Shia community in shock following execution
The New Zealand Shia community is in shock following news of the execution of prominent Shia cleric Sheikh Nimr Al-Nimr by Saudi authorities.
Seyed Mohammad Taghi Derhamy moved to Auckland in 1985. The Irani-born accountant is an active member of the Shia community, and often leads Friday prayers at his local mosque.
He has followed the sermons of Sheikh Nimr Al-Nimr for years, and said the cleric was part of his community's identity.
Yesterday, he awoke to news of his execution.
"It is a very, very wrong thing to do, wretched thing to do, ugly thing to do. Whatever you want to call it, it is."
A few months ago, Mr Derhamy organised rallies in Auckland to support the cleric and maintained his innocence.
He said the community felt injured by the death of a figure who fought for the rights of the religious minority in Saudi Arabia.
"He was not a criminal. His life was books, and studies and speeches and writing and of course, courage.
"He was courageous to come out at talk."
Sheikh Nimr Al-Nimr was arrested four years ago following mass anti-government protests in Saudi Arabia's Eastern Province, where Muslims of the Shia minority have long complained of marginalisation by the sunni-led government.
The international rights group, Reprieve, called last week's executions "appalling", and said the death of Al-Nimr and three others were related to political protest.
Abdul Monem Nasser, a retired university lecturer from Iraq, told RNZ Sheikh Al-Nimr was pushing for democracy.
"We feel very sad for the execution of a scholar, and we believe he is a prisoner of conscience, and all his opposition was for democracy and freedom of thought.
"This killing is not warranted by any means."
Dr Nasser said freedom of speech and thought was guaranteed by the United Nations, but also by Islam.
"None of the Muslims were killed for their opinion during the time of the Prophet Muhammad at all.
"On the contrary, he said 'you have your opinions, I have my opinions'."
Yesterday, protesters in Iran, angered by news of the execution, stormed the Saudi Embassy in Tehran and set fire to the building.
Saad Khayyat - a trustee of the Ahlul Bayt Community Centre on Auckland's North Shore - condemned the violent protests, and said that was not what Sheikh Al-Nimr stood for.
"If you listen to his speeches, he was a person who was advocating human rights, equal rights for all citizens regardless of their ethnicity or their religion."
"He always instructed peaceful demonstrations, but demonstration is a human right, people have the right to demonstrate to say no to injustice."
Mr Khayyat said there was a double standard in the way the international community treated Saudi Arabia, despite a track record of human rights violations.
He said while many groups have already condemned the execution, he'd like to see the New Zealand government lead the way and do so as well.
Executions 'appalling' - Greens
The New Zealand government has spoken out against all the executions, with duty minister Sam Lotu-Iiga saying New Zealand was a longstanding opponent of the death penalty.
But he would not comment on whether trade negotiations with Saudi Arabia would be put on hold.
Green Party co-leader James Shaw has renewed calls for the talks to be suspended.
"The executions are appalling and just another example of Saudi Arabia's terrible record on human rights. The Greens have been calling for a long time for New Zealand to suspend negotiations on the free trade agreement with Saudi Arabia because we don't think we should be giving preferential treatment to a country that has this kind of record."
But the Labour Party said trade talks with Saudi Arabia were an opportunity for New Zealand to raise the country's human rights record.
Labour foreign affairs spokesperson David Shearer did not agree with the Greens on the issue.
"Trading links enables us ot get a foot in the door to talk about human rights issues that we would not otherwise be able to do if we didn't have those links. I don't believe it's necessarily in our interests to take this stance in banning trading talks with either country."
Iran: Saudis face 'divine revenge'
Saudi Arabia will face "divine revenge" for the execution, Iran's supreme leader Ayatollah Ali Khamenei has warned.
Ayatollah Khamenei described Sheikh Nimr al-Nimr as a "martyr" who acted peacefully.
Protesters stormed the Saudi embassy in Tehran late on Saturday, setting fire to the building before being driven back by police.
Several hundred people gathered outside the building again on Sunday afternoon.
The authorities have changed the name of the street on which the Saudi embassy stands, naming it after Sheikh Nimr.
Ayatollah Khamenei said the cleric had been executed for his opposition to Saudi Arabia's Sunni rulers.
"This oppressed scholar had neither invited people to armed movement, nor was involved in covert plots," the ayatollah tweeted.
"The only act of #SheikhNimr was outspoken criticism," he added, saying the "unfairly-spilled blood of oppressed martyr #SheikhNimr will affect rapidly & Divine revenge will seize Saudi politicians".
Fury in Iranian press
Newspapers in Iran have reacted with anger to the killing of the Shia cleric, warning it could bring down the Saudi ruling family but Saudi papers insist the authorities have the right to mete out punishment to those who do not obey the rules.
The killing "has brought the weak foundations of the bloodthirsty government of Saudi Arabia closer to collapse", says Iran's hard-line Vatan-e Emruz.
The authorities in Riyadh (the Capital of Saudi Arabia) must now accept that the supporters of the cleric in the region "will take revenge", warns conservative Hemayat.
But reformist Sharq fears the "irresponsible" act could exacerbate sectarian tensions in the region and warns Tehran not to get drawn into Riyadh's "dangerous game".
In Saudi Arabia, Al-Riyadh is adamant that "the homeland's security, unity and prestige are non-negotiable" and no "incitement of harm or sedition" should be tolerated irrespective of the culprit's affiliations.
Finally, Al-Jazirah, says the "firm, strong verdict" has made the country "safer and more stable".
- additional reporting BBC