The Foreign Office (FCO) has warned travellers the security situation across the Middle East "could worsen with little warning" amid growing tensions between Iran and the west.
The FCO has significantly toughened its stance on travel to the region in recent days after a top Iranian general was killed in a US airstrike near Baghdad on Friday (3 January).
It is advising against all travel to Iraq, except essential travel to the country’s Kurdistan region, and all but essential travel to Iran.
Any Britons in either Iran are urged to "consider carefully" their need to remain. "If your continued presence is not essential, you should consider leaving," said the FCO.
On Monday afternoon (6 January), the FCO also amended its travel advice for more than a dozen other countries in and around the region.
These include Turkey, Egypt, the United Arab Emirates, Jordan, Qatar, Oman, Kuwait and Saudi Arabia.
"The incident has led to increased tensions in the region," said the FCO. "There is a possibility of an increased threat against Western interests and the security situation could worsen with little warning."
Iran has vowed to avenge the death of Qasem Soleimani and has rolled back on its commitments to a 2015 deal limiting its nuclear capabilities. US president Donald Trump has threatened to impose additional sanctions on Iran and potentially attack Iranian cultural sites.