Israeli and Palestinian negotiators were to meet again on Monday in a fresh effort to salvage the teetering, US-brokered peace process, US and Palestinian officials said. "Israeli and Palestinian negotiators met last night to discuss ways to overcome the crisis in the talks," a US official said. Accompanied by US envoy Martin Indyk, the two sides met on Sunday evening, but Palestinian sources told AFP that the session ended without any breakthrough and an Israeli official was quoted by local media as saying the process was on the edge of collapse. Prime Minister Benjamin Netanyahu on Sunday threatened to retaliate if the Palestinians proceed with applications to sign up to 15 international treaties.