Lord Cameron has not ruled out the possibility of further strikes against Houthi rebels in Yemen, arguing the UK must do “what is necessary” to protect its ships.

Speaking to NBC, Sky News’s sister outlet in the United States, the foreign secretary said “warnings” issued to the rebels – who had been attacking UK and US ships in the Red Sea – had not been “working”.

On Thursday night the UK and US launched air strikes against a number of military facilities used by the Iran-backed Houthis in Yemen, receiving non-operational support from Australia, Bahrain, Canada and the Netherlands.

The UK government has described the strikes as an act of “self defence” after branding the attacks on commercial ships as “unacceptable”.

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But asked whether there was a risk that the UK could get pulled into launching repeated further strikes, the foreign secretary said: “We will do what is necessary to protect our ships to protect maritime freedom of navigation on important maritime pathways.”

He added: “But be clear what we were doing – warning – was not working.

“The number of attacks was increasing the severity of those attacks was increasing. This escalation has been caused by the Houthis. And this action is in response to that to send a very clear message that if you act in this way, there aren’t just warnings there are consequences.”

On Friday the prime minister’s official spokesperson said there were currently “no further plans” to launch strikes to restore the shipping lanes, but that the UK keeps its security “under review”.

The UK and US launched the action – which killed five people – after Houthi rebels attacked a series of commercial ships, beginning in November.

The Iranian-backed group of Shia Islamists, who are based in western Yemen, ignored repeated warnings to stop targeting ships in the Red Sea.

Tensions were inflamed further this week after after a British warship, in an operation with US forces, shot down seven drones launched by Houthis to repel the largest drone and missile attack to date.

The Houthis have claimed the attacks are aimed at ending the air and ground offensive in Gaza following the Hamas attack on Israel on 7 October.

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The Ministry of Defence (MOD) said four Royal Air Force jets struck two Houthi facilities that had been involved in the targeting of HMS Diamond and US Navy vessels on Tuesday.

One facility was a site at Bani and the other was the Abbs airfield, which is used to launch drones and cruise missiles.

The US Air Force said it struck more than 60 targets at 16 sites in Yemen.

While France and Germany have offered their backing to the move, Turkey has argued that the action against the Houthi rebels was not “proportional”.

Its president, Recep Tayyip Erdogan, accused the US and UK of trying to turn the Red Sea into a “sea of blood”.

Lord Cameron dismissed those criticisms, saying he believed the joint action with the US was “proportionate” and “legal”.

“It was absolutely right to do,” he added. “And I think it sends a very clear message to the Houthis – but also to Iran as well.”

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Rishi Sunak is expected to make a statement to MPs on Monday about the military strikes against the Houthis following criticism that MPs were not consulted on the plans.

The Liberal Democrats have called for a retrospective vote on the military action in the Red Sea and called for MPs to be recalled to parliament before Monday, with foreign affairs spokesperson Layla Moran saying: “Parliament should not be bypassed.

“We remain very concerned about the Houthis’ attacks. But that makes it all the more important to ensure that MPs are not silenced on the important issue of military action.”