Iran-US war latest: Trump issued fresh demands to end war by Tehran as smoke and flames seen at Riyadh Airport

Iran has laid out to Donald Trump its conditions for re-engaging in negotiations aimed at ending the war with the US, security chief Mohsen Rezaei said.

The conditions include ending the war on all fronts, unfreezing Iranian funds and ending the naval blockade, Rezaei said in an interview according to Al Jazeera.

Discussions with Qatari and Pakistani mediators are ongoing, he added, as the delegations work to bring an end to the stalemate which has seen the war drag past the six-month mark.

It comes amid fears of war widening in the region as violence between the Iran-aligned Houthi rebels and Saudi Arabia escalates.

A large plume of black smoke was seen near ⁠Riyadh's main airport on Saturday after booms were heard. Saudi Arabia sent alerts overnight warning of potential danger around the capital and the city of Al-Kharj, before issuing an all-clear on Saturday morning.

The Houthis , who control the most populous parts of Yemen and much of the north, have been launching attacks towards Saudi Arabia since declaring a naval blockade against Riyadh in July, with strikes targeting Saudi vessels in the Red Sea.

The US State Department on Saturday renewed a blanket travel alert for Americans in or traveling to the Middle East, warning that the conflict with Iran "has the potential to escalate rapidly."

Security alerts for Bahrain, Oman, Saudi Arabia, Iran, Qatar, Lebanon, Kuwait and Jordan warned the regional security environment “remains complex with the potential for unforeseen escalation.”

Meanwhile, at least 11 US embassies in the region issued a warning that travel disruptions are possible.

The head of Iran's Supreme National Security Council, Mohsen Rezaei, told Al Jazeera in an interview that Iran has conveyed its conditions for ending the war to the US via Qatar and it is waiting for President Donald Trump's response.

Rezaei said they include ending the war on all fronts, releasing assets seized from Iran and ending the US naval blockade of Iranian ports. Earlier US-Iran negotiations fell apart.

He also said Iran wants the fighting involving Yemen and Saudi Arabia to end.

President Donald Trump cut short his stay at Camp David and returned to the White House on Saturday evening, a day earlier than scheduled, as his administration weighs its next steps in the war with Iran.

Trump arrived at Camp David late Friday and had been expected to remain there until Sunday. The White House did not give a reason for his early return.