British Prime Minister Boris Johnson said that the Iranian general killed in a U.S. drone strike in Iraq was “a threat to all our interests” and that “we will not lament his death.”

Johnson, who spoke with U.S. President Donald Trump on Sunday, called for de-escalation from all sides.

“All calls for retaliation or reprisals will simply lead to more violence in the region and they are in no one's interest," the U.K. leader said.

It was the first statement from Johnson on soaring Mideast tensions since Iranian Gen. Qassem Soleimani was killed in Baghdad on Friday.

Prior to the statement, the British leader had been criticized for remaining silent on the issue and not cutting short his vacation on the private Caribbean island of Mustique during the escalating crisis. Johnson is now back in the U.K.

Soleimani “posed a threat to all our interests and was responsible for a pattern of disruptive, destabilizing behavior in the region,” Johnson said. “Given the leading role he has played in actions that have led to the deaths of thousands of innocent civilians and Western personnel, we will not lament his death.”

Johnson celebrated the New Year on Mustique after leading his Conservative Party to a strong majority in the Dec. 12 election.

Soleimani’s death stoked fears that heightened world tensions could spiral into war after Iran threatened revenge against the U.S, which has sent 3,000 more soldiers to Kuwait.

Before Johnson's statement, British Foreign Secretary Dominic Raab had defended the prime minister from opposition criticism, saying the two had been in constant contact.

The British government has upgraded its travel warning for the Middle East and dispatched two warships to escort U.K.-flagged ships passing through the Strait of Hormuz, a key shipment corridor for world oil supplies.

Jeremy Corbyn, the outgoing leader of the opposition Labour party, said Johnson “should have immediately cut short his holiday to deal with an issue that could have grave consequences for the U.K. and the world.”

In an op-ed in The Observer, Labour’s foreign policy spokeswoman Emily Thornberry, who is in the race to take over from Corbyn, said she was astonished Johnson hadn't said anything 48 hours after the strike and wondered if he was afraid of angering U.S. President Donald Trump, who ordered the slaying.

Ed Davey, the leader of a smaller party, the Liberal Democrats, tweeted that Johnson's silence was “deafening.”

Raab, appearing Sunday morning on British news shows, dismissed the criticism, telling Sky News that “the whole government is working closely together. We’re very clear on strategy.”

“Johnson has been in charge from the outset," he told the BBC. “In fact, I've been in constant contact with the PM over the Christmas break on a whole range of foreign policy issues."

Later this month, Johnson aims to fulfil his major campaign promise and “get Brexit done," taking Britain out of the European Union as scheduled on Jan. 31. The U.K. then embarks on intense negotiations to hash out a trade deal with the EU, Britain's top trading partner.

The Labour Party, meanwhile, is casting about for a new leader a fter the worst showing since 1935 in December's general election. A raft of contenders are vying take over, with five candidates so far declaring their intention to run, including Labour's Brexit spokesman Keir Starmer, who's seen as the frontrunner, high-profile lawmaker Jess Philips and Thornberry.

The party's executive committee will meet Monday to set the timetable for the leadership contest, which is expected to formally open Tuesday. The new leader is expected to be in place by the end of March.