The Palestinian leader has warned US President Barack Obama that he will pull out of upcoming peace talks if Israel ends a slowdown on West Bank settlement construction, a Palestinian negotiator said Monday. President Mahmoud Abbas sent a letter to Obama stressing that any renewed Israeli settlement construction would end the talks, said Palestinian negotiator Saeb Erekat. The direct negotiations are to begin in Washington next week, after months of US diplomatic efforts. Both sides seem pessimistic about the chances of success. Israel must chose between “settlements or peace,” Palestinian chief negotiator Erakat said. “The choice of the Israeli government is settlement or peace, they cannot have both,” he said at a news conference in Ramallah, the political capital of the Israeli-occupied West Bank. But he also said he believed agreement could be reached within one year. “We think it is doable.” Israel's 10-month slowdown, which bars construction of most new homes in the West Bank, is supposed to end in late September, and Israel's government is split over whether to extend it. Erekat said that Abbas also sent the letter to the European Union, the UN and Russia - all members of the Mideast Quartet of mediators, along with the US. While Israeli Prime Minister Benjamin Netanyahu and other Israeli officials have said in the past that the slowdown would not be extended, the Israeli government is now signaling that it might be flexible. “The government has yet to announce officially what will be done. For the moment, the most important thing is to get the talks going, and we're not going to do anything to give the Palestinians an excuse to derail the talks,” said Yigal Palmor, a spokesman for Israel's Foreign Ministry. Netanyahu has not commented on the issue of the freeze since the US announced Friday that talks would be resuming in Washington next week. It will be the first face-to-face peace talks between the sides since late 2008. Obama hopes to forge a deal within one year.