Iran and the United States exchanged new threats on Sunday, with President Donald Trump warning Iran would fail ‌economically or face its leadership being wiped out if it didn’t make a deal, and the Iranian military saying it would retaliate harshly to any fresh attack.

The conflict has looked stalemated for months, with no sign either side was ready for concessions even as it has deepened a global energy crisis, cratered swathes of Iran’s economy and spilled over into new regional escalations, Reuters reported.

In a ​phone call with a Fox News reporter, Trump said Iran’s leaders should make a deal, rot economically or be wiped out, the reporter said.

However, ​with Iran’s President Masoud Pezeshkian expected in New York this week for the United Nations General Assembly, Trump said he would ⁠be open to meeting him, the Fox reporter added.

Trump has repeatedly made vague threats of major military escalations during the conflict that began with US and Israeli ​strikes on February 28, without carrying them out.

Earlier, Iran’s military central command said any new attack would trigger sustained retaliation against US bases and interests and that ​Washington’s regional allies would be considered parties to the conflict.

The Iranian military added that it had information that an attack was being prepared, without elaborating on what that information might be.

HOUTHIS TARGET RIYADH

US Gulf allies have already been badly scarred by a war that the US and Israel launched with no warning, bringing their cities under Iranian fire and hammering their economies with the ​crucial Strait of Hormuz waterway blockaded.

On Saturday their predicament worsened further, with Yemen’s Iran-backed Houthi group launching missile and drone strikes at the Saudi capital after having ​made sudden military gains in Yemen’s reignited civil war earlier this month.

Reuters video showed a massive plume of black smoke billowing from the area of Riyadh’s main international airport following booms ‌overnight.

The US ⁠State Department issued a security alert citing the Houthi hostilities. It said there was potential for unforeseen escalation in the Middle East, and Americans should exercise more vigilance and be aware of possible flight cancellations and airspace closures.

Saudi Arabia did not comment on the incident, though a Saudi-led coalition fighting the Houthis said it had foiled other attacks on the kingdom.

Recent escalation by the Houthis has forced Riyadh into a painful dilemma: continue airstrikes on the group to stop it seizing more Yemeni ​territory or step back in the hopes ​of averting drone strikes on critical ⁠infrastructure.

ENERGY EXPORTS BLOCKADED

The Houthi gains along the coast mean the group’s forces now sit on the Bab el-Mandeb Strait, giving them easier control over shipping travelling between the Red Sea and Asia and the ability to blockade the crucial waterway.

With Iran already ​having blockaded most shipping in the Strait of Hormuz, the oil-rich Gulf’s energy exports are now almost entirely cut ​off from global markets, ⁠adding to pressure on oil prices.

A US blockade of Iranian ports is meanwhile stopping Iran from selling its own oil, contributing to major problems in the Islamic Republic’s economy.

Despite the economic damage, there is little sign of a return to the interim ceasefire agreement that was struck in June but fell apart in July amid disputes over its terms.

Iran reiterated ⁠on Sunday that ​it would not reopen the Strait of Hormuz until the terms of that June agreement, as ​it interpreted them, were met.

Iranian Parliament Speaker Mohammad Baqer Qalibaf said Iran would have to keep on fighting as well as negotiating, to push back its enemies and to consolidate any gains with diplomacy.

Yemen’s Houthis said they attacked “sensitive” sites in the Saudi capital Riyadh on Saturday with missiles and drones, hours after flames and a large ​plume of smoke were seen near the city’s main airport.

Saudi Arabia had sent alerts overnight warning of potential danger around Riyadh, amid an escalation in attacks ‌by the Houthis in the kingdom, Reuters reported.

Reuters video and photographs showed a huge pillar of black smoke rising in the area, with the airport highway, main terminal building and other facilities in the foreground. At one point in the video, flames were visible rising from behind what appeared to be fuel tanks.

While the Iranian-backed Houthis have launched repeated attacks against Saudi Arabia since July, Saturday’s claim appeared to be their first reported strike on Riyadh since ​the current escalation began.

The Houthis did not specify what they had targeted in Riyadh, but said they had also attacked an Aramco facility in the Red Sea city of ​Yanbu, a key Saudi oil export hub.

They said the operation came as a response to an attack in the Yemeni capital Sanaa.

The Saudi-led military ⁠coalition fighting the Houthis said its air defences had destroyed a missile fired by the Yemeni group toward Riyadh early on Saturday.

In a statement, the coalition also said it had foiled ​attacks targeting civilians in the Saudi cities of Bish and Farasan in the southwest and Taif in the west, as well as Yanbu on the Red Sea coast. It did not say whether ​there was any damage.

Saudi civil defence sent the alerts by phone overnight for potential danger of aerial attacks in Riyadh and the city of Al-Kharj east of the capital, before issuing an all-clear on Saturday morning. A Reuters journalist in Riyadh’s Olaya area heard booms before the all-clear was sent.

Although some alerts had been issued in Riyadh this year after the start of the US-Iran war, these were the first since the escalation with the ​Houthis began in July.

The fighting between the Houthis and Saudi Arabia has developed as a new theatre of conflict in the wider war that began with US and Israeli strikes against Iran ​at the end of February. US President Donald Trump has rebuffed Saudi requests for direct US military intervention against the Houthis.

A US State Department security alert issued on Saturday for Americans in the Middle East ‌cited Houthi attacks. ⁠The State Department urged US citizens in the region to “exercise heightened vigilance” and that Americans outside the Middle East “should seriously reconsider travel to and through the region.”

HOUTHI WARNING

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

The attacks have targeted Saudi cities, energy infrastructure and shipping, creating new threats to global oil supplies and putting at risk the main alternative Red Sea route for Gulf exports while traffic through the Strait of Hormuz ​remains blockaded.

Turkish Foreign Minister Hakan Fidan said Saudi ​Arabia may have military needs due to ⁠the ongoing Houthi attacks and Turkey was ready to help under a trilateral defence pact that also includes Pakistan.

It was unclear what kind of support Turkey might provide but Fidan, in an interview with broadcaster NTV, said Saudi needs could include “some technical issues.”

The trilateral agreement signed last month stipulates ​that an armed attack on any of the three countries would be regarded as an attack on all of them.

Mohsen Rezaei, secretary ​of Iran’s Supreme National Security ⁠Council, told Al Jazeera in an interview aired on Saturday that Tehran wanted the war between Saudi Arabia and the Houthis to end, adding that he believed Yemenis also wanted a settlement with Saudi Arabia.

Rezaei also said Iran had conveyed its conditions to mediators for re-engaging in stalled negotiations with the United States, including “ending the war on all fronts”.

Consultations were continuing with Qatari and Pakistani mediators and Tehran was awaiting ⁠a response ​from Trump, Rezaei said.

The UN Security Council in a statement on Friday “condemned in the strongest terms continued Houthi attacks ​against the Kingdom of Saudi Arabia, including attacks impacting civilian and energy infrastructure, which have resulted in the injury of civilians, including women and children.”

In the statement, the Security Council also condemned “Houthi military escalation in Yemen”.

Iran executed a man convicted ​of passing missile ‌site intelligence to Israel during the ​12-day war, according ​to the judiciary.

Iran’s judiciary-run ⁠Mizan news ​agency said Hossein Pedaran ​was hanged after the Supreme Court upheld ​his death sentence ​on charges of espionage ‌and ⁠intelligence cooperation with Israel, Reuters reported.

It said Pedaran had provided Israel’s ​Mossad ​intelligence ⁠service with information on sensitive ​military sites ​in ⁠the central province of Isfahan, and ⁠had ​carried out ​the espionage for financial ​gain.