Arab and Muslim leaders demanded on Monday that Israel withdraw from occupied Palestinian territories as a precondition for regional peace, while denouncing "shocking" Israeli crimes in war-ravaged Gaza.

A summit meeting in the Saudi capital gave the Arab League and the Organisation of Islamic Cooperation's 57 nations a chance to speak with one voice on turmoil unfolding across the region, more than a year into the Israel-Hamas war in the Gaza Strip.

It came less than a week after Donald Trump secured a second term as president of the United States, Israel's top military backer.

The summit's closing statement said that "a just and comprehensive peace in the region... cannot be achieved without ending the Israeli occupation of all occupied Arab territories to the line of June 4, 1967," referring to the occupied West Bank and east Jerusalem as well as Gaza and the Golan Heights.

The statement mentioned UN resolutions which have called on Israel to withdraw from these areas, and the 2002 Arab Peace Initiative, in which Arab nations offered Israel normalised ties in return for a two-state agreement with the Palestinians along the 1967 lines.

The international community should "launch a plan with specific steps and timing under international sponsorship" to make a sovereign Palestinian state a reality, the statement said.

The hard-right Israeli government of Prime Minister Benjamin Netanyahu remains implacably opposed to Palestinian statehood, a point driven home earlier on Monday when Israel's newly appointed foreign minister, Gideon Saar, dismissed the prospect as not "realistic".

Israeli Finance Minister Bezalel Smotrich later vowed to push for annexation of parts of the West Bank in 2025.

Monday's statement from the summit in Riyadh reiterated regional leaders' call for Palestinian territories -- including Gaza, which is separated from the West Bank by Israeli territory -- to be grouped together in a future state.

The leaders also condemned "horrific and shocking crimes" by Israel's army in Gaza, saying they occurred "in the context of the crime of genocide".

The war began with Hamas's unprecedented attack on Israel on October 7 last year, which resulted in 1,206 deaths, mostly civilians, according to an AFP tally of Israeli official figures.

Israel's retaliatory campaign has killed more than 43,600 people in Gaza, most of them civilians, according to figures from the Hamas-run territory's health ministry that the United Nations considers reliable.