The Iran-backed Houthi militia group has continued to attack commercial shipping, hitting an American-owned container ship with a ballistic missile in defiance of a wave of US and UK strikes on Yemen. The strike against the Marshall Islands-flagged Gibraltar Eagle container ship represented a widening of the theatre of war beyond the Red Sea to the Gulf of Aden. The strike hit the cargo hold of the ship and while it was thought to have caused no major damage, will add to fears that the US and UK strikes on Houthi targets in Yemen have not degraded the militia group’s ability to threaten commercial shipping. Qatar became the latest major user of container ships to announce it will not send liquid gas through the Red Sea for the foreseeable future. The level of traffic was said to have dropped markedly overall since the US and UK strikes on Thursday. The Houthis, an Iranian-backed Shia group that has been battling for control of Yemen for more than 20 years, say the more than 30 attacks on commercial shipping over the past six weeks are part of an effort to put pressure on Israel to allow more humanitarian aid into Gaza. The Houthis’ chief negotiator, Mohammed Abdulsalam, said on Monday that the group’s position had not changed after the US-led strikes, and indicated that strikes would continue on ships heading to Israel: “Our position on the events in Palestine and the aggression against Gaza has not changed and would not change, neither after the strike nor after the threats. “The attacks to prevent Israeli ships or those heading to the ports of occupied Palestine are continuing.” The Houthis say an Israeli ceasefire in Gaza would immediately lead to the free flow of ships through the Red Sea, and lift pressure on global supply chains. The Houthis’ comparative success on Monday raises questions about whether the US-UK naval alliance off Yemen will have to mount a further series of strikes, or even consider liaising actively with ground troops from the UN-recognised Presidential Leadership Council (PLC) – the Saudi-UAE backed coalition government based in Aden. The UK defence secretary, Grant Shapps, said the attacks on the Houthis mounted on Thursday night had been intended as “a single limited action” rather than a continuing series of attacks. Rishi Sunak, the prime minister, told MPs he hoped the Houthis would step back after the “necessary and proportionate response”, but added “the UK would not hesitate to protect our security and our interests”. “We remain prepared to back our words with action,” he said. On Sunday a US fighter jet also shot down a Houthi-fired cruise missile fired from Houthi areas and aimed at the US destroyer USS Laboon. Earlier on Monday, the UK Maritime Trade Operations agency reported an unidentified ship had fended off two small vessels seeking to board. In addition on Monday, US Central Command said that two hours before the strike on Gibraltar Eagle, a cruise missile fired from Houthi-controlled areas failed in flight and landed in the sea causing no damage. Yemeni sources said residents had heard explosions close to the port of Hodeidah, implying the US and UK were continuing to mount operations in an attempt to snuff out the threat posed by Houthi missiles. Many of the strikes on Thursday night were aimed at Hodeidah. A leading member of Yemen’s UN-recognised government urged the west to provide his forces with military equipment, training and intelligence to help defeat the Houthis. The Aden-based Maj Gen Aidarus al-Zoubaidi, the deputy head of the eight-strong PLC, said the near nine-year attempt by the Saudis to defeat the Houthis showed air power was not enough. He claimed many Houthi missiles would be hidden underground and hard to detect. The UK ambassador to Yemen, Abda Sharif, on Sunday met with the PLC prime minister, Dr Maeen Abdul Mali, to discuss the future of the UN peace plan for Yemen, and how to prevent the Houthi movement riding a popular wave of support by projecting itself as one of the few groups in the Middle East willing to show active solidarity with the Palestinians in Gaza. At the weekend big Houthi crowds chanted: “We don’t care and make it a world war.” After a meeting in Aden on Monday, the PLC made a point of distancing itself from Israel, voicing “Yemen’s support for the legitimate rights of the Palestinian people, most notably in resisting the Israeli occupation and establishing its independent, fully sovereign national state”. The statement warned the Houthi militias of “the consequences of continuing to exploit the oppression of the Palestinian people in order to achieve Iran’s interests and its expansionist projects in the region”. It said Houthi actions only served to distract the world’s attention away from the Israeli occupation’s attacks and “grave violations” in a way that served the continuation of the “aggression”. The PLC wants the Houthi militia to be classified as a terrorist group, a designation that the US president, Joe Biden, withdrew soon after becoming president. Such a designation would make it difficult for humanitarian agencies to cooperate with Houthi-linked Yemen groups.