Mr Sunak has met Israeli President Isaac Herzog and Prime Minister Benjamin Netanyahu.
Mr Netanyahu embraced Mr Sunak as the pair met, and Mr Sunak could be heard saying: “Hello my friend, very good to see you.”
After their meeting, the pair held a brief news conference, in which Mr Netanyahu thanks Mr Sunak for his support.
Mr Netanyahu said the current situation will be “a long war”, and Israel will “need” the UK’s “continual support”.
Mr Sunak said he welcomed the opening of a humanitarian corridor into Gaza.
He added that he knew Israel was “taking every precaution to avoid harming civilians – in contrast to the terrorists of Hamas”.
Mr Sunak said he was “proud” to stand with Israel in its “darkest hour”.
The UK leader is on a two-day trip to the region, and will meet with counterparts from across the Middle East, according to Downing Street, including Crown Prince Mohammed bin Salman of Saudi Arabia. Foreign Secretary James Cleverly is also in the region.
In their meeting, Mr Herzog and Mr Sunak “stressed the imperative need to avoid further escalation of violence”.
A Downing Street spokesperson said: “The prime minister met Israeli President Isaac Herzog in Israel today.
“He expressed his personal condolences for the horrific loss of life in Israel as a result of Hamas’s terrorism. He reiterated that the UK stands in solidarity with Israel and firmly believes in the country’s right to self-defence in line with international law.
“The prime minister and President Herzog agreed on the importance of getting urgent humanitarian support to ordinary Palestinians in Gaza who are also suffering. The prime minister welcomed yesterday’s announcement that Israel would not stop aid from entering Gaza. He expressed his sincere hope that further progress could be made on delivering crucial food, water and medicine.
“The prime minister conveyed his gratitude to President Herzog for the support Israel has provided to British nationals caught up in the attacks, including to the families of those who have been taken hostage. The leaders agreed to continue working tirelessly to secure their release.
“The prime minister and President Herzog stressed the imperative need to avoid further escalation of violence in the region. They agreed to continue working together to that end.”
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Rishi Sunak arrives in Jerusalem
Mr Herzog thanked Mr Sunak for the visit afterwards, saying: “We are at the frontier of a certain class of civilisation. We are seeing an ISIS on our border, entering in our country.
“It is an empire of evil that we know is led by terror.”
Hamas officials claimed the hospital blast killed hundreds of people and was caused by an Israeli airstrike – but the Israeli military blamed a misfiring rocket from the Palestinian Islamic Jihad group and released imagery and communications intercepts to support their case.
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