UNITED NATIONS (AP) — A senior U.N. official warned Monday that lack of progress on a two-state solution to the Israel-Palestinian conflict ensures that a new round of violence "is never too far below the surface."

Assistant Secretary-General Jens Toyberg-Frandzen told the U.N. Security Council's monthly Mideast meeting that Secretary-General Ban Ki-moon is alarmed at the escalation of tensions in Jerusalem and deeply concerned that violence has spread elsewhere in Israel and the West Bank.

A recent escalation of violence between Palestinians and Israelis was sparked by rising tensions over a disputed site in Jerusalem that is the most sacred place in Judaism and the third holiest site for Muslims after Mecca and Medina in Saudi Arabia. Palestinians have clashed with Israeli police over access to the site, and there have been a spate of Palestinian attacks and killings of Israelis as well as Israeli clashes and shootings of Palestinians.

Toyberg-Frandzen criticized Israel's continued settlement activity in violation of international law, saying the new construction "continues to undermine efforts to calm the tensions in Jerusalem."

He also criticized Israel's increasing demolition of Palestinian buildings, which also violates international law, and "is also contributing to rising animosity in Jerusalem." He noted that 82 structures including 47 homes have been demolished in the West Bank and East Jerusalem since Oct. 21, displacing 169 Palestinians.

Toyberg-Frandzen urged Israelis and Palestinians to demonstrate "responsible leadership, avoid taking provocative unilateral actions," refrain from using inflammatory rhetoric to incite supporters, and return to peace talks.

"Without a genuine commitment from the parties, and an overall improvement in the lives of Palestinians, we should anticipate further deterioration of the security situation and an expansion of the current violence," he said.

On a positive note, Toyberg-Frandzen said a U.N.-brokered agreement to get building materials into Gaza to rebuild the territory following this summer's war between Israel and Hamas allowed 1,086 Gazans to purchase construction materials by Nov. 13. He said it is also encouraging that Israel plans to increase the number of trucks with construction materials entering Gaza from the current 300 to 800 daily.

But Toyberg-Frandzen said 60,000 shelters remain in urgent need of repair, 80,000 Gazans still don't have homes, and $62 million worth of U.N. construction projects are still awaiting Israeli approval.