Indonesian President Joko Widodo urged Israel to end the occupation of Palestinian territories, saying international patience "has long run out," at the opening Monday of a summit.

"As part of the international community, Israel must immediately stop its illegal activities and policies in occupied territories," Joko said in a speech opening an extraordinary summit of the Organization of Islamic Cooperation (OIC) in Jakarta.

"Indonesia and the Islamic world are ready to take concrete steps to push Israel to end its colonization of Palestine and its arbitrary actions in al-Quds al-Sharif," he said, using the Arabic name for Jerusalem.

Palestinians want Jerusalem to be the capital of their future state.

The summit, organized at the request of the Palestinian Authority, planned to discuss the deteriorating situation in Palestinian territories and reaffirm the grouping's support for Palestinian independence.

Delegates from 49 of the 57 OIC member countries attended. A handful sent heads of state, while most were represented by foreign ministers or other officials.

Sudan's President Omar al-Bashir was among those present, defying an arrest warrant by the International Criminal Court (ICC) for alleged war crimes.

Indonesia is not a party to the ICC statute.

Palestinian President Mahmoud Abbas warned that Israel's continuing expansion of illegal settlements was threatening the two-state solution.

"We work constantly to bring back our land and ... to establish a national unity government," Abbas said in his speech at the summit.

"We have approached our brothers in Gaza," he said, referring to Hamas, which controls that part of the Palestinian territories. "If there is goodwill, if there is a desire, we can establish a unity government in a few months."