The chief Palestinian peace negotiator threatened on Tuesday that there would be no talks with Israel unless a deadline is set for establishing a Palestinian state — the first indication the Palestinians could scuttle a U.S.-sponsored peace summit over the issue.

Palestinian officials have repeatedly said they want a detailed timeline for talks that are expected to begin in earnest after a U.S.-sponsored Mideast conference in November or December. But although Israeli Prime Minister Ehud Olmert has consistently resisted the notion of a deadline, they had never before made the matter a condition for talks.

On Tuesday, lead negotiator Ahmed Qureia tightened the screws.

"The Israeli prime minister has stated that he will not accept a timetable, and we say we will not accept negotiations without a timetable," Qureia said at a news conference with the European Union's external affairs commissioner, Benita Ferrero-Waldner.

He delivered the ultimatum as the two sides struggle to bridge yawning gaps ahead of the fall peace summit. It wasn't clear whether the Palestinians would really carry out the threat, or were trying to wrest concessions from Israel.

In the past, however, deadlines have been set and ignored.

No date has been set for the U.S.-sponsored summit, set to take place in Annapolis, Md., because the two sides remain so far apart on the starting point for talks. Israel wants a vague, joint statement of objectives. The Palestinians want a detailed outline that would address core issues that need to be resolved before peace can be achieved and a Palestinian state can be established.

These are final borders, sovereignty over disputed Jerusalem, and a solution for Palestinians who fled or were expelled from their homes in the war that followed Israel's creation in 1948.

Olmert and Palestinian President Mahmoud Abbas have met several times in recent months to try to come up with a joint platform ahead of the meeting, and negotiating teams from both sides have recently entered the process.

At Tuesday's news conference, Qureia indicated the talks weren't going well.

"We haven't gotten closer yet concerning the issues," he said. "We are talking in general about the issues that should be included in the document. (But) we haven't yet touched the core issues."

What the Palestinians want, he said, is "a clear and specific document, without vagueness, that lays the basic foundation for all final status issues. Without that, the conference will be hindered."

Qureia was one of the negotiators of the 1993 accord Israel and the Palestinians reached in the Norwegian capital of Oslo, which called for a final peace deal five years later.

In 2007, the Palestinians are still waiting, and "we don't want to go for open-ended negotiations," he said Tuesday.

Israeli government spokeswoman Miri Eisin said negotiations should be held behind closed doors, not through the media.

"We're not at the ultimatum stage," Eisin said. "They agreed to work to go forward, and we are committed to going forward to a joint statement."