Rishi Sunak has not ruled out launching a “sustained” military campaign against the Houthis in Yemen.
The UK joined the US in a second wave of strikes on the Iranian-backed group in the country late last night.
RAF Typhoons struck “multiple targets at two military sites in the vicinity of Sanaa airfield” with precision-guided bombs, the Ministry of Defence said.
In a statement to MPs on Tuesday afternoon, the prime minister said the action was taken in “self-defence” to protect civilian shipping in the Red Sea.
“I just want to be absolutely clear that no decision has been taken to embark on a sustained campaign. These are limited strikes specifically in response to threats we perceived,” he said.
The prime minister added: “But we do reserve the right to take action in self-defence.”
Sunak was responding to a question from Tory MP Jeremy Quin, the chair of the Commons defence committee, who asked if a “prolonged and persistent targeted campaign” might be needed.
Lib Dem leader Ed Davey has demanded parliament be given not just a debate on UK military action - as is due tomorrow - but a vote.
“It is deeply disappointing that elected representatives are being bypassed on an issue as important as military action,” he said.
Downing Street has so far rejected the calls, arguing there is no legal “requirement” for MPs to vote on authorising the use of force.
London and Washington have said the airstrikes are designed to deter Houthi drone and missile attacks on commercial shipping.
The Houthi have said its campaign is aimed at disrupting the Israeli offensive in the Gaza Strip.
But Sunak told the Commons today this was simply “propaganda” and the two conflicts were unrelated.
“The Houthi’s have carried out attacks on multiple ships from different counties - many of who have nothing to do with situation in Israel and Gaza,” he said.
The prime minster added was “no link” between UK-US strikes in Yemen and what is happening in Gaza.
Earlier, No.10 admitted Keir Starmer and Lindsay Hoyle were not told about the latest bombing raids before they happened - despite transport minister Huw Merriman claiming this morning that they had been.
The Labour leader and Commons Speaker were both advised in advance advance about the first bombing raids.