Sir Keir Starmer will travel to Germany on Friday for talks with Joe Biden, Olaf Scholz and Emmanuel Macron on the situation in the Middle East.

The leaders of the UK, the US, Germany and France will discuss the deteriorating humanitarian crisis in northern Gaza, where the UN has warned essential supplies for survival are running out, as well as the need for a hostage deal and de-escalation, Downing Street said.

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The meeting comes a day after Israel said it had killed Hamas leader Yahya Sinwar, who is believed to have masterminded the 7 October attacks in 2023 that triggered the war.

Sir Keir said the UK “will not mourn his death” in a statement released ahead of travelling to Germany.

“As the leader of the terrorist group Hamas, Yahya Sinwar was the mastermind behind the deadliest day in Jewish history since the Holocaust, as 1,200 people were slaughtered in Israel,” the prime minister said.

“Today my thoughts are with the families of those victims. The UK will not mourn his death.

“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.”

US President Joe Biden said 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 failed to produce a breakthrough.

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However, Israeli premier Benjamin Netanyahu said the country will keep fighting until all Israeli hostages are free, and that it will keep control of Gaza long enough to ensure Hamas does not re-arm.

In his speech about Sinwar’s death, Mr Netanyahu said: “Our war is not yet ended.”

The war in Gaza is now more than a year old – with Israel having killed more than 42,000 Palestinians in response to Hamas’ incursion last year, according to the Gaza health ministry.

Hamas killed some 1,200 people and captured around 250 hostages when its militants entered Israel on 7 October.

At the meeting, the leaders will also discuss the latest situation in Ukraine, following the presentation of President Zelenskyy’s victory plan to his country’s parliament earlier this week.