Rishi Sunak has urged Saudi Arabia to help support stability in the Middle East, after backing Israel in its war with Hamas on a visit to the country.
The UK prime minister agreed to work with Saudi Crown Prince Mohammed bin Salman to avoid further escalation and deliver aid to Gaza.
Mr Sunak flew to Riyadh as part of a two-day trip to capitals in the region.
Earlier, Mr Sunak promised to stand with Israel in a meeting with Prime Minister Benjamin Netanyahu.
The diplomatic flurry comes as Israel prepares for a ground invasion of Gaza after the deadly Hamas attack on 7 October.
Speaking at a joint press conference with the Israeli President, Mr Sunak said he was “proud” to support Israel in its “long war” against Hamas, which he branded “pure evil”.
In a statement following the meeting with the Saudi crown prince, the UK Prime minister said the pair agreed the “loss of innocent lives in Israel and Gaza over the last two weeks has been horrific” and “underscored the need to avoid any further escalation in the region”.
Mr Sunak “encouraged the crown prince to use Saudi’s leadership in the region to support stability, both now and in the long-term”.
Israeli warplanes and artillery have been bombarding Gaza since more than 1,400 people were killed in the attack by Hamas earlier this month.
Gaza remains under siege, with Israel blocking cross-border supplies of water, electricity, and fuel.