The US Virtual Embassy in Iran issued a security alert telling Americans not to travel to the country “for any reason” and those already there to leave immediately, citing possible flight cancellations, airspace closures and changing land border rules, according to Fox News and the ANI news agency.

The notice recalls that Washington has no embassy or consular presence in Iran, with Switzerland acting as protecting power for US interests, and advises citizens to plan alternative means of communication. On Saturday, the State Department had already told Americans in the Middle East to exercise heightened vigilance and prepare for travel disruption, after new Houthi attacks on Saudi Arabia. The alert repeats guidance issued several times this year and comes on the eve of the United Nations (UN) General Assembly, with an Iranian proposal to end the war still unanswered by Washington and the US blockade of Iranian ports in place.