WASHINGTON, Sept 29 (Reuters) - European Union foreign policy chief Catherine Ashton said she would depart for the Middle East on Wednesday as diplomatic pressure intensified to save faltering Israel-Palestinian peace talks.

"I'm going to the Middle East tonight and and I'll meet (U.S. Middle East peace envoy) George Mitchell when I land tomorrow," Ashton told Reuters in an interview in Washington, adding that she also planned to meet Israeli Prime Minister Benjamin Netanyahu and Palestinian President Mahmoud Abbas.

Ashton's trip, which follows talks in Washington with U.S. Secretary of State Hillary Clinton, comes as Mitchell seeks to salvage peace talks that plunged into crisis after a 10-month moratorium on new housing construction in Israeli settlements in the occupied West Bank expired on Monday.

Mitchell emerged from a meeting with Netanyahu on Wednesday with no public sign of progress toward the goal of averting a Palestinian walkout over the settlements.

The European Union, the United States, the United Nations and Russia make up the "quartet" of Middle East peace mediators. Ashton said she would join Mitchell in seeking to find a way to keep the talks alive.

The United States, Israel's closest ally, has been traditionally the main peace broker in the decades-old Middle East conflict. Europe has tended to play a backup role.

"The challenge is to find a way that we can keep President Abbas in the talks," Ashton said, adding that she believed Abbas and Netanyahu were having serious talks about the way forward.

"The impression I get is that ... they're having a conversation, and the rapport between them, doing that, appears to be very good," Ashton said.

"So in terms of Middle East peace possibilities, this is probably as good as it's been for a very long time."

Abbas has threatened to quit the direct talks that were launched on Sept. 2 unless the settlement freeze is extended. He has put off a decision until an Arab League forum discusses the issue on Oct. 4.

Netanyahu, whose governing coalition is dominated by pro-settler parties including his own right-wing Likud, had rebuffed calls by U.S. President Barack Obama and other foreign leaders to extend the partial freeze.

But Netanyahu has held out the prospect of limiting the scope of renewed building, and Ashton said there might be other ways of persuading the Palestinian leader to stick with the talks.

"The question then becomes: is there something else that can make a difference. Are there other things that, if Abbas had instead, would be sufficient to allow him at least to carry on for a while," Ashton said.

The standoff over settlements is another sign of the hurdles the Obama administration faces in its quest for an Israeli-Palestinian peace deal that has eluded predecessors. Many analysts are skeptical that the talks will succeed.

WAITING FOR AN ANSWER

Ashton said next week's Arab League meeting would provide an important clue on whether Abbas and his chief diplomatic backers have decided to remain in the talks.

"I think we'll know in the next week whether the talks are in grave danger of collapse or whether there's been a way through," Ashton said.

She added that a collapse of the negotiations could make it more difficult for Obama to broker any future Middle East peace deals -- which might necessitate a larger role for the European Union and other mediators.

"The danger for the Middle East is that the president has so many priorities to worry about, not least domestic politics, that his attention gets dragged back to that," Ashton said.

She said that French President Nicolas Sarkozy's invitation to Netanyahu, Abbas and Egyptian President Hosni Mubarak for peace talks in Paris before the end of October was intended in part to show that Europe was ready to make its contribution.

"If things change then that's one of the things that we'll have to discuss: is there more that we can do?" Ashton said. "President Sarkozy's invitation is, in a sense, his way of saying we're here too and we're willing to help."