Israeli President Isaac Herzog is due to attend the UN climate talks on Thursday in the United Arab Emirates, where he will hold talks with diplomats on the release of hostages held by Hamas.
His visit comes seven weeks into the Gaza war and coincides with a day-long extension of truce that had been due to expire on Thursday, amid ongoing attempts to release more hostages.
At COP28, which will also be attended by Palestinian President Mahmoud Abbas, Herzog will hold a "series of diplomatic meetings on the importance of releasing the hostages held by Hamas", the Israeli presidency said in a statement.
He "intends to engage world leaders in a high-level humanitarian effort to return the hostages", the statement said.
More than 140 heads of state and government are due to address COP28 on Friday and Saturday, including Herzog and Abbas who are both scheduled to make speeches lasting three minutes on Friday.
Since the truce began on Friday, 70 Israeli hostages have been freed in return for 210 Palestinians held by Israel.
Around 30 foreigners, most of them Thais living in Israel, have been freed outside the terms of the deal.
Israel has made clear it sees the truce as a temporary halt intended to free hostages, but there are growing calls for a more sustained pause in the conflict.
The truce agreement has put a pause to fighting in Gaza, where authorities say almost 15,000 people have been killed in Israel's military campaign. Israeli authorities say some 1,200 people were killed and around 240 taken hostage in Hamas's surprise 7 October attack inside Israel.
The war has cast a shadow over the UN climate talks in Dubai with activists planning actions to express solidarity with Gaza.
On Thursday, climate activists will hold a press conference to demand a permanent ceasefire in Gaza and an end to Israel's 17-year blockade of the enclave.
"The climate movement see the struggle of the Palestinian people against occupation and apartheid as part and parcel of our collective struggle for climate" justice, said a statement by the COP28 Coalition, a global network of climate justice and human rights organisations.