The UN political chief warned Tuesday that chances of peacefully ending the Israeli-Palestinian conflict may be "irreparably damaged" unless steps are taken to prevent new Israeli settlement building and other "negative developments."

Jeffrey Feltman told the Security Council that four months since the resumption of Israeli-Palestinian talks aimed at a two-state solution, negotiators "have gone some way toward narrowing their differences."

But he said "strains have been growing dangerously between the parties, and these can and must be overcome."

Feltman cited "a significant setback" following a series of Israeli announcements of settlement plans in the West Bank and East Jerusalem, especially the Nov. 13 announcement of 24,000 new units, including in the sensitive E-1 area.

Palestinians say construction there would close one of the last open spaces between east Jerusalem, which the Palestinians want as the capital of their future state, and the West Bank where many Palestinians live. Prime Minister Benjamin Netanyahu has asked the housing minister to reconsider the expansion plans.

"We hope that these plans are suspended," Feltman said, adding that Secretary-General Ban Ki-moon wants "a full stop" because settlements violate international law and are an obstacle to peace.

In protest at the settlement expansion announcements, Feltman said Palestinian negotiators have submitted their resignations, which are now under consideration by President Mahmoud Abbas.

He said Abbas has made it clear that "this does not constitute a Palestinian departure from (peace) talks."

Feltman urged the Israelis and Palestinians to intensify efforts to reach a settlement "and refrain from actions that undermine trust and the spirit of talks."

He cited the deteriorating situation in Hamas-ruled Gaza, where there is renewed violence and worsening economic and humanitarian conditions.

Specifically, he said, Israeli security forces carried out over 350 search-and-arrest operations in the past month, violence between settlers and Palestinians continued on a daily basis throughout the West Bank, and an Israeli soldier was stabbed to death in the Israeli city of Afula.

Feltman stressed that a two-state solution remains the only way to realize the legitimate aspirations of Palestinians and Israelis "for self-determination, peace and security."

"The consequences of failure would be dire for Israelis and Palestinians alike," he said.

"We thus continue to urge the parties to remain steadfast in their commitment to see this process through," Feltman said. "But we fear that unless steps are taken to prevent the reoccurrence of negative developments such as those of recent weeks, the remaining chances to achieve a negotiated two-state solution may be irreparably damaged."