"I renew my fervent appeal to allow for the entry of fair humanitarian help and to bring to an end to the hostilities, the devastating price of which is paid by children, the elderly and the sick," the new Pope said on Wednesday during his first weekly general audience in St Peter's Square.
Leo, the former cardinal Robert Prevost, was elected the leader of the Catholic Church on May 8 to succeed the late Pope Francis.
He has mentioned the situation in Gaza several times in the first weeks of his papacy.
The appeal came at the end of the Pope's audience, when he added a few words to his prepared text.
The Pope, who US President Donald Trump said on Monday had expressed interest in hosting Russia-Ukraine peace talks, did not mention that conflict.
In his first Sunday message on May 11, the new pontiff called for an immediate ceasefire in Gaza and for the release of all Israeli hostages held by militant group Hamas.
Israel said on Monday that it would allow aid to enter Gaza after an 11-week blockade on the enclave, but the United Nations said no help had been distributed as of Tuesday.
Israel says it plans to intensify military operations against Hamas and to control the whole of Gaza, which has been devastated by an Israeli air and ground war since Hamas's cross-border attack on Israeli communities in October 2023.
Israel has said its blockade is aimed in part at preventing Palestinian militants from diverting and seizing aid supplies.
Hamas has denied doing so.
Francis, who died on April 21, had been ramping up criticism of Israel's military campaign in Gaza in the months before his death.
He called the situation in the enclave "very serious and shameful" in January, two months after suggesting the international community should study whether there had been a genocide of the Palestinian people.
Reflecting a chill in Vatican-Israel relations after Francis's criticisms, Israel, unlike many other nations, did not send a high-level official to attend the late pope's funeral, but only its Vatican ambassador.
In a sign of possible hopes for a reset of relations with the new Pope, Israeli President Isaac Herzog attended Leo's inaugural Mass in St Peter's Square on Sunday.
10°C