Rishi Sunak has said the UK is willing to take military action against Houthi rebels again, hours after the Yemen-based group fired another missile at a container ship in the Red Sea. The prime minister addressed MPs on Monday for the first time since the UK took part in airstrikes on the Houthis on Friday night, which he said destroyed 13 targets at two sites, including drones, an airfield and a cruise missile launcher. He defended the decision to launch the strikes without parliament’s approval, and warned the UK could launch more if the rebels continued to hold hostages and posed a threat to international shipping in the region. Sunak told the Commons: “This action was taken in self-defence. It was limited, not escalatory. It was a necessary and proportionate response to a direct threat to UK vessels and therefore to the UK itself.” But he added: “The threats to shipping must cease. Illegally detained vessels and crews must be released. And we remain prepared to back our words with actions.” The prime minister’s comments bolster those made earlier on Monday by the defence secretary who told an audience in central London that the UK did not intend to launch another attack but could do so if necessary. Grant Shapps said: “Although this was a distinct piece of precisely targeted military action, we will not put up with a major waterway, major shipping lanes being closed on a permanent basis.” On Friday 10 countries, led by the US, joined forces to strike the Houthis, who promptly promised to retaliate. On Sunday the US said one of its fighter jets had shot down a missile aimed at one of its warships in the region, and on Monday it said the Houthis had fired on a US-operated container ship. The strikes were welcomed by Britain’s main opposition parties, including Labour, whose leader, Keir Starmer, told MPs on Monday: “The UK strikes were limited, targeted and did everything possible to protect civilian lives. That is a proportionate response.” However, several MPs questioned why parliament was not recalled to debate the action first. Ed Davey, the Liberal Democrat leader, called the lack of a parliamentary debate “regrettable”, while Starmer said: “Scrutiny is not the enemy of strategy.” Sunak said he remained committed to the idea of consulting parliament before taking sustained military action, a principle that was set with the parliamentary vote on the Iraq war and prevented the government taking action in Syria in 2013. “It was necessary to strike at speed … to protect the security of these operations,” the prime minister said. “That is in accordance with the convention and I remain committed to that convention and would always look to follow appropriate processes and procedures and also act in line with precedent.” Some MPs said western strikes on Houthi targets risked escalating the crisis in the Middle East. The Labour MP Zarah Sultana said: “Military intervention starting out as limited can quickly escalate, risking a sequence of events far larger and more terrible, and risk even dragging us into war.” Sunak rejected what he called the “malign narrative” that the attacks in the Red Sea were connected to the Israel-Gaza conflict. But he added that he would speak to other world leaders in the region to make sure they did not interpret the international strikes as seeking to intervene in that war. “There will be maligned forces out there that seek to distort our action to turn it into something that it is not,” he said. “It’s important that we engage with our allies and those others in the region so they understand what we did and why.”