Rex Tillerson has accused Iran of “alarming and ongoing provocations” that export terror and destabilise the world after a friendly meeting with Saudi leaders.

“Iran is the world’s leading state sponsor of terrorism and is responsible for intensifying multiple conflicts and undermining US interests in countries such as Syria, Yemen, Iraq, and Lebanon, and continuing to support attacks against Israel,” he said.

“An unchecked Iran has the potential to travel the same path as North Korea, and take the world along with it.”

The US Secretary of State said a government-wide review of American policy on Iran was underway, following Donald Trump’s repeated criticism of a landmark deal struck by the Obama administration to limit its nuclear capability.

Mr Tillerson said the review would assess the “many threats posed by Iran” and establish whether the suspension of sanctions related to the agreement was “vital to the national security interests of the United States” – even through Tehran is in compliance.

“Iran’s provocative actions threaten the United States, the region, and the world,” he added.

Russia and Iran have threatened the US over Syria

Mr Tillerson cited Iran’s support for Bashar al-Assad in Syria and Houthi rebels in Yemen, as well as its hostility to Israel as threats, alongside attempted assassinations abroad, weapons tests and cyber attacks.

He accused Iran of having “one of the world’s worst human rights records”, listing executions and political persecution, but made no mention of similar abuses perpetrated in Saudi Arabia at a business summit earlier in the day.

In a speech watched by Prince Saud al-Faisal, ministers and the ambassador, Mr Tillerson hailed “a successful new chapter” for relations between Saudi Arabia and the US, and their “shared economic and strategic goals”.

“We have a long relationship with Saudi Arabia that extends over 80 years, and our support for a strong and steady partner on economic cooperation remains as firm as ever,” he added, weeks after Saudi leaders met Donald Trump in Washington.

Saudi Arabia is a member of the US-led coalition bombing Isis in Syria and Iraq but has drawn accusations of war crimes for its intervention in Yemen, where thousands of civilians have been killed in indiscriminate bombardment.

The US, Britain and the Kingdom’s other allies have been urged to stop arms sales and military support over the deaths, as well as extensive human rights abuses on its own soil.

Alongside Iran and China, Saudi Arabia is one of the world’s most prolific executioners, publicly beheading convicts - including those arrested as children - according to the government’s interpretation of Sharia law.

10 examples of Saudi Arabia's human rights abuses Show all 10 1 /10 10 examples of Saudi Arabia's human rights abuses 10 examples of Saudi Arabia's human rights abuses In October 2014, three lawyers, Dr Abdulrahman al-Subaihi, Bander al-Nogaithan and Abdulrahman al-Rumaih , were sentenced to up to eight years in prison for using Twitter to criticize the Ministry of Justice. AFP/Getty Images 10 examples of Saudi Arabia's human rights abuses In March 2015, Yemen’s Sunni President Abd-Rabbu Mansour Hadi was forced into exile after a Shia-led insurgency. A Saudi Arabia-led coalition has responded with air strikes in order to reinstate Mr Hadi. It has since been accused of committing war crimes in the country. Getty Images 10 examples of Saudi Arabia's human rights abuses Women who supported the Women2Drive campaign, launched in 2011 to challenge the ban on women driving vehicles, faced harassment and intimidation by the authorities. The government warned that women drivers would face arrest. Getty Images 10 examples of Saudi Arabia's human rights abuses Members of the Kingdom’s Shia minority, most of whom live in the oil-rich Eastern Province, continue to face discrimination that limits their access to government services and employment. Activists have received death sentences or long prison terms for their alleged participation in protests in 2011 and 2012. Getty Images 10 examples of Saudi Arabia's human rights abuses All public gatherings are prohibited under an order issued by the Interior Ministry in 2011. Those defy the ban face arrest, prosecution and imprisonment on charges such as “inciting people against the authorities”. Getty Images 10 examples of Saudi Arabia's human rights abuses In March 2014, the Interior Ministry stated that authorities had deported over 370,000 foreign migrants and that 18,000 others were in detention. Thousands of workers were returned to Somalia and other states where they were at risk of human rights abuses, with large numbers also returned to Yemen, in order to open more jobs to Saudi Arabians. Many migrants reported that prior to their deportation they had been packed into overcrowded makeshift detention facilities where they received little food and water and were abused by guards. Getty Images 10 examples of Saudi Arabia's human rights abuses The Saudi Arabian authorities continue to deny access to independent human rights organisations like Amnesty International, and they have been known to take punitive action, including through the courts, against activists and family members of victims who contact Amnesty. Getty Images 10 examples of Saudi Arabia's human rights abuses Raif Badawi was sentenced to 1000 lashes and 10 years in prison for using his liberal blog to criticise Saudi Arabia’s clerics. He has already received 50 lashes, which have reportedly left him in poor health. Carsten Koall/Getty Images 10 examples of Saudi Arabia's human rights abuses Dawood al-Marhoon was arrested aged 17 for participating in an anti-government protest. After refusing to spy on his fellow protestors, he was tortured and forced to sign a blank document that would later contain his ‘confession’. At Dawood’s trial, the prosecution requested death by crucifixion while refusing him a lawyer. Getty Images 10 examples of Saudi Arabia's human rights abuses Ali Mohammed al-Nimr was arrested in 2012 aged either 16 or 17 for participating in protests during the Arab spring. His sentence includes beheading and crucifixion. The international community has spoken out against the punishment and has called on Saudi Arabia to stop. He is the nephew of a prominent government dissident. Getty

Its fundamentalist Wahhabi doctrine is used as the basis for severe restrictions on fundamental rights, including the discriminatory male guardianship system that bans women from driving, while dozens of activists have been arrested and sometimes flogged for calling for government reforms.

Saudi Arabia, where 15 of the 9/11 attackers hailed from, has also been accused of fuelling global terror by funding extremist mosques around the world.

Mr Trump heavily criticised the Saudi government on Twitter before his election victory but has since remained silent, while fostering a close relationship and excluding the country from his attempted immigration bans.

The President and his Defence Secretary, James Mattis, have instead turned on Saudi Arabia’s enemy Iran, repeatedly calling it the “world’s biggest state sponsor of terrorism” and accusing it of forming militias compared to Hezbollah.

Iran and Saudi Arabia, who hail themselves as the global leaders of Shia and Sunni Islam respectively, are engaged in a global proxy war drawing in conflicts in Syria, Yemen, Iraq and Lebanon.

Mr Tillerson sent a letter House Speaker Paul Ryan announcing the policy review on Tuesday, saying the nuclear deal had merely “delayed Iran’s goal of becoming a nuclear state”.

Iran’s Supreme Leader, Ayatollah Khamenei, warned in November that Tehran would retaliate if the US breached the nuclear agreement and has called mass protests against Mr Trump.

Mr Tillerson's notice to Congress was part of a 90-day process in which the President has to certify that Iran is complying with the nuclear accord.