Sir Keir Starmer has arrived in Berlin ahead of a meeting with the leaders of the US, France and Germany.
The so-called “Quad” meeting on Friday afternoon is expected to discuss the war in Ukraine and the spiralling conflict in the Middle East.
The Prime Minister was greeted by Chancellor Olaf Scholz as he arrived ahead of the discussions.
The planned trip to the German capital comes after Israel announced on Thursday its military had killed Hamas leader Yahya Sinwar, presenting his death as a turning point in the country’s campaign against the group.
The White House confirmed that US President Joe Biden would meet Sir Keir and French President Emmanuel Macron to discuss “the pathway ahead in Ukraine” and “the ongoing and fast-moving developments across the Middle East”.
Mr Biden said Mr Sinwar’s killing was a “good day for Israel, for the United States, and for the world”, with officials in Washington expressing muted optimism that his death may remove a key obstacle in ceasefire talks that have so far failed to produce a breakthrough.
Sir Keir said the UK “will not mourn” the death of the mastermind behind Hamas’ October 7 attacks as he repeated calls for an immediate ceasefire in the Middle East.
“The release of all hostages, an immediate ceasefire and an increase in humanitarian aid are long overdue so we can move towards a long-term, sustainable peace in the Middle East,” he said.
However, Israeli Prime Minister Benjamin Netanyahu said the country will keep fighting until all Israeli hostages are free, and that it will keep control over Gaza long enough to ensure Hamas does not rearm.
Earlier this month Israel also opened a new front in its war with Hezbollah, stepping up bombardment in Lebanon and a ground offensive after a year of trading fire across borders.
Mr Sinwar’s death is a crippling blow to Hamas, but the group has proven resilient after the losses of previous leaders.
He became the overall leader of Hamas in July after his predecessor Ismail Haniyeh was killed in an apparent Israeli strike in the Iranian capital Tehran.
In his speech about Mr Sinwar’s death, Mr Netanyahu said: “Our war is not yet ended.”
