RAMALLAH, West Bank — Mahmoud Abbas, the Palestinian president, refused Tuesday to publicly commit to restarting suspended talks with Israel, frustrating Bush administration officials who contended that he was giving Hamas, the militant Islamist organization, a tactical victory by allowing it to hijack Arab-Israeli peace negotiations.

After a meeting with Secretary of State Condoleezza Rice, Mr. Abbas did not say that he would never return to talks. He just refused to say when, and seemed to relish a new role of standing up to the United States and Israel.