UNITED NATIONS - The prospect of peace between Israelis and Palestinians is fading by the day as violence and radicalism grow - and "the risk of war continues to loom large", a senior UN envoy in the region warned on Wednesday.

Nikolay Mladenov, the special coordinator for the Middle East peace process, also told the UN Security Council that a negotiated two-state solution is drifting further away.

"What is needed, first and foremost, is the necessary leadership and political will for change," he said. "Until that will can be found, Palestinians and Israelis will continue to slide into increasingly hazardous territory."

Mladenov said leaders must believe peace is possible through negotiations - and that leaders and the international community must be committed to support Israelis and Palestinians to reach a peace deal based on UN resolutions and bilateral agreements.

He said the international community must also understand that "the weaker party - the Palestinian people who have lived under occupation for more than 50 years - need our support more than ever".

"Unfortunately, unilateral measures, continuing violence, financial pressures and the lack of progress toward peace are exacting a heavy toll on Palestinian society and undermining the foundations of peace," Mladenov said.

He said Hamas' continuing control of Gaza, severe restrictions on movement imposed by Israel, "and the Palestinian Authority's restrictive measures are pushing the situation to a breaking point".

"The militant buildup continues as the risk of ever more radical and extremist groups pushing both sides into war grows by the day," the UN envoy warned.

He said that with prospects of reconciliation between the Palestinian factions dimming, people in Gaza "feel more and more left to their own devices".

Last month, he outlined steps to support stability for the Palestinian Authority including expanded trade opportunities, addressing financial issues, increasing services for its people, and ensuring security coordination with Israel.

He said these measures "are not a substitute for peace".

These must be matched by Israel, he said, including ending its policy of settlement construction and expansion and creating opportunities for Palestinian development in Area C in the West Bank, which is under exclusive Israeli control and home to dozens of Israeli settlements.

Associated Press