The US-Israeli war with Iran has expanded with the entry of Houthi forces in Yemen, representing a dangerous spread of the conflict and bringing with it the threat of more damage to the global economy.

Pakistan has said it would host a meeting of Middle Eastern powers on Monday in an effort to find a regional approach to ending the conflict. But the talks, which bring together the foreign ministers of Saudi Arabia, Turkey and Egypt, did not appear to include any of the warring parties, casting further doubt on persistent US claims of diplomatic progress.

Houthi forces, close allies of Iran, said on Saturday they had fired a salvo of ballistic missiles at “sensitive Israeli military sites” and that they would continue military operations until the “aggression” came to an end on all fronts. Israel said it had intercepted one missile originating in Yemen.

Despite US claims to have devastated Iran’s military, Reuters cited intelligence sources as saying Washington could only be certain it had destroyed a third of Iran’s missile and drone arsenal.

US media reported that a missile and drone attack on Prince Sultan airbase in Saudi Arabia wounded at least 12 US soldiers, two of them seriously. Drones also struck Kuwait international airport on Saturday, causing significant damage to its radar system.

The entry of the Houthis, who control Yemen’s most populous areas, poses a direct threat to the Bab al-Mandab strait at the southern end of the Red Sea, a second major choke point in the supply chain of energy supplies and other trade in and out of the Middle East.

With Iran’s near total closure of the strait of Hormuz, a shutdown of the Bab al-Mandab, located between Yemen and the Horn of Africa, would amplify the already grave impact of the war on the global economy, and could also reignite a Saudi-Yemen conflict that caused huge humanitarian suffering for seven years before a 2022 truce.

Since the US-Israeli attack on Iran on 28 February, Saudi Arabia has been able to divert some of its oil exports by pipeline to the Red Sea. Saudi commentators have said that if this route was also threatened, Riyadh could also enter the war directly.

Farea Al-Muslimi, a research fellow in Middle East and north Africa programme at the Chatham House thinktank, said: “The decision by the Houthis to join the broader Middle East conflict marks a serious and deeply concerning escalation.

“The potential impact on key commercial maritime routes, especially in the Red Sea and the Bab al-Mandab strait, cannot be overstated. At the same time, vital economic and military infrastructure across the Gulf region may become increasingly exposed.”

In a further sign of the war’s potential to spread, Iran’s central operational command said it had targeted a Ukrainian anti-drone system depot in Dubai, which it said was assisting US forces. There was no immediate confirmation of the strike from Dubai authorities.

Ukraine has been providing anti-drone technology and expertise to the Gulf states since the war began, drawing on years of experience of being attacked by Russia with Iranian-designed fixed-wing unpiloted aircraft.

The Ukrainian president, Volodymyr Zelenskyy, announced on Saturday that his country and the United Arab Emirates had agreed to cooperate on defence and visited Qatar on Sunday, as Ukraine sought to widen its network of allies.

There was also evidence of escalation in the array of weapons being used in the conflict with reports that the US has dropped cluster munitions. Experts cited by Bellingcat said that mines photographed in an Iranian village near a missile base in Shiraz were Gator anti-tank mines, a cluster munition that has been banned by more than 100 countries because of its indiscriminate nature. The US is the only party in the Iran conflict to possess the weapon, though Tehran has been using ballistic missiles carrying cluster warheads as part of its strikes on Israel.

As the war entered its second month, Pakistan has sought to act as a peace broker. The country’s prime minister, Shehbaz Sharif, and army commander, Field Marshal Asin Munir, had hoped to encourage US-Iran talks. Donald Trump has claimed, without evidence, that such contacts had already started and were “going very well”, while Tehran denied there had been any talks at all.

Sharif said on Sunday that he had held “extensive discussions” with Iran’s president Masoud Pezeshkian, briefing him on Pakistan’s diplomatic efforts.

It is unclear how much a regional meeting without any of the protagonists can achieve. Saudi Arabia’s crown prince, Mohammed bin Salman, has privately been urging Trump to escalate the offensive against Iran, apparently anxious that a wounded but undefeated regime in Tehran could be one of the worst possible outcomes for Riyadh.

Trump suggested on Friday night that he had hoped Bin-Salman would join four other Arab countries in normalising relations with Israel in return for the attack on Iran, Saudi Arabia’s longstanding rival in the region.

The US president said: “Mohammed would say: ‘Oh yes. As soon as we do this. As soon as we do that.’ It’s now time. We’ve now taken them out, and they are out bigly. We’ve got to get into the Abraham Accords.”

Trump was speaking at a Saudi-sponsored investors meeting in Miami, where he sought to talk up the US economy’s prospects in the face of the oil price shock caused by the war and a consequent sell off of stocks.

The survival of the Islamic Republic’s regime after a month of bombing has left Trump with the choice of looking for a way to extricate the US from the costly war or intensifying the campaign, possibly including ground troops. Thousands of US marines and airborne forces have been deployed in the region in recent days, raising speculation of a land incursion on Kharg island, Iran’s main oil export hub, or on islands in the Hormuz strait.

Tehran has warned that, if that happened, it would completely shut down the strait and escalate its attacks on regional infrastructure, including desalination plants essential for the water supply in several Gulf countries.

Such an escalation, possibly combined with renewed direct confrontation between Saudi Arabia and the Houthis, could lead to a major regional conflagration, Al-Muslimi said.

“Any such war would likely be more intense, more destructive, and even more devastating than previous rounds of fighting,.”