US peace talks envoy Martin Indyk and his team have not taken part in any negotiating sessions between Israel and the Palestinians despite assurances that they would do so, senior Palestinian official Yasser Abed Rabbo charged on Thursday.Abed Rabbo was quoted by official Palestinian news agency WAFA as saying that the the Americans had not participated in the talks because of "an Israeli stance and demand,” adding that “this is one sign of how and where the talks are heading if the US is not able now to assert itself in the peace process.”Negotiations between Israelis and Palestinians restarted in Washington earlier this month after a prolonged push by US Secretary of State John Kerry for their resumption. Israeli and Palestinian negotiators have met three times in Jerusalem since then, twice on Tuesday and once last week in Jerusalem. “The Americans did not participate in any negotiating session so far in spite of assurances that they will play a direct role,” WAFA quoted Abed Rabbo as saying.Indyk and his team were present in Jerusalem during the talks, but did not sit in on the negotiations, the PLO official said.Abed Rabbo reiterated Palestinian warnings that continued Israeli settlement activities could lead the PA to abandon the talks."The negotiations will end up with a disastrous outcome without any real alternatives if the settlements continue along with negotiations,” Abed Rabbo said. "The situation on the ground does not show any positive signs so far,” he added.Chief Palestinian negotiator Saeb Erekat was in Moscow on Thursday, where he met with Russian Foreign Minster Sergei Lavrov. Lavrov urged Israel and the Palestinians to rebuild trust. "We understand that you are only at the very start. We want the resumed talks to assume stability," AFP quoted him as saying."We want the negotiations to achieve the result that we are all after -- a final settlement, including all the issues concerning final status, so that a Palestinian state emerges that lives in peace and security together with Israel and other nations," the Russian foreign minister added.