The chief Palestinian negotiator said Monday that he believed reaching an agreement with Israel within a year was 'doable,' echoing remarks by Israel's prime minister a day earlier that a peace agreement would be difficult but 'possible.' But the otherwise sharply differing declarations presented as the basis for going into the direct talks, scheduled to start in Washington on Sept. 2, reflect the complexity of the effort required to get the two sides to this point and the daunting challenges that lie ahead. At a news conference here at the administrative headquarters of the Palestinian Authority, Saeb Erekat, the chief negotiator, said the leadership had accepted the invitation to return to direct talks, which broke off in late 2008, based on the statement issued Friday by the quartet of Middle East peacemakers: the United States, United Nations, European Union and Russia. The Palestinian Authority president, Mahmoud Abbas, this month complained to reporters in Ramallah that he was under almost unbearable international pressure to return to direct talks. The quartet's statement, issued alongside the announcement of the start of talks by Secretary of State Hillary Rodham Clinton, was intended to satisfy Palestinian demands for terms of reference for the talks, given that Israel and Clinton rejected any 'preconditions.' The Palestinians wanted assurances that the goal of the talks would be a Palestinian state based on the pre-1967-war lines and that the talks would be accompanied by a freeze of all Israeli settlement construction. In reality, the carefully worded statement was itself a compromise. It reaffirmed the quartet's commitment to previous statements, which called for a settlement that 'ends the occupation which began in 1967' and results in the emergence of a Palestinian state, and which called on Israel to freeze all settlement activity and to refrain from demolitions, evictions and other provocative acts in East Jerusalem. But the quartet's statement made no new, explicit call for a settlement freeze, adding to a cloud of uncertainty over the talks. The first major test for the Israeli prime minister, Benjamin Netanyahu, is expected around Sept. 26 when Israel's partial, 10-month moratorium on settlement construction is to expire. 'If Mr. Netanyahu decides to renew settlement tenders come September 26, he will have decided to stop negotiations,' Erekat said. He added that Abbas had sent letters to President Barack Obama and other quartet leaders urging them to take a 'strong and unequivocal position regarding Israel's obligation to freeze all settlement activity, without exceptions.' 