“Indirect talks offer a chance to evaluate Washington’s seriousness about a political solution with Iran,” said the official.

Although that path could be “rocky”, such talks could begin soon if U.S. messaging supported it, the official said.

Iran has issued notices to Iraq, Kuwait, the United Arab Emirates, Qatar, Turkey and Bahrain that any support for a U.S. attack on Iran, including the use of their air space or territory by U.S. military during an attack, would be considered an act of hostility, the official said.

Such an act “will have severe consequences for them”, the official said, adding that Supreme Leader Ayatollah Ali Khamenei had placed Iran’s armed forces on high alert.

Warnings by Trump of military action against Iran have jangled already tense nerves across the region after open warfare in Gaza and Lebanon, military strikes on Yemen, a change of leadership in Syria and Israeli-Iranian exchanges of fire.

Worries of a wider regional conflagration have unsettled states around the Gulf, a body of water bordered on one side by Iran and on the other by U.S.-allied Arab monarchies that carries a significant proportion of global oil supplies.

Spokespeople for the governments of Iraq, Kuwait, the UAE, Qatar and Bahrain did not immediately respond to requests for comment. Turkey’s Foreign Ministry said it was not aware of a warning but that such messages could be conveyed by other channels.

On Wednesday, Iranian state media reported that Kuwait had reassured Iran that it would not accept any aggressive action being directed at other countries from its soil.

Iran’s ally Russia said on Thursday that U.S. threats of military strikes against the Islamic Republic were unacceptable and on Friday called for restraint.

Iran is trying to gain more support from Russia, but is sceptical about Moscow’s commitment to its ally, said a second Iranian official. This “depends on the dynamics” of the relationship between Trump and Russian President Vladimir Putin, the official said.