"There are so many issues out there that don't seem to have been resolved," one U.S. official said, citing gaps on security matters as one of the stumbling blocks to a deal on a long-overdue Israeli troop pullback from more of the West Bank.
Ross's mission, his first since May, follows 18 months of deadlock in a peace process launched five years ago next Sunday with the signing in Washington of the Oslo interim accords between Israel and the Palestine Liberation Organisation (PLO).
Ross was scheduled to meet Palestinian President Yasser Arafat on Wednesday night in the Palestinian-ruled West Bank town of Ramallah, Palestinian officials said.
Plans for a meeting on Thursday with Prime Minister Benjamin Netanyahu in Jerusalem were in doubt after the Israeli leader was laid low by influenza.
The United States withdrew from direct negotiations in May after Israel refused to follow Palestinians in agreeing in principle to a U.S. initiative that includes proposals for a pullback from an additional 13 percent of the West Bank.
"Since that time, there's been movement, significant movement on the key issues, including the size of the further redeployment," Rubin said in Washington.
But he cautioned that "there is plenty of work to do, and I would not read the phrase 'a few days' to indicate that we are on the verge of an agreement, because we are not."
Meanwhile, Greek and Arab leaders expressed concern at a growing military alliance between the Jewish State and mainly Moslem but officially secular Turkey.
Israel's Defense Ministry announced Tuesday that the two non-Arab Middle East countries would hold a second round of naval maneuvers in the east Mediterranean, and would invite Jordanian and Egyptian participation.
It added that the two countries also planned to hold air force exercises, but no date had been set yet.
Egyptian Foreign Minister Amr Moussa called the military relationship a "negative development" and said that Egypt would not take part in the exercizes.
"Egypt...does not consider these maneuvers as timely or necessary and anyway there is no such invitation and they had better not issue an invitation," Moussa said.
Greek officials expressed concern that the alliance would equip Turkey with Israeli technology that could be used against Greece should long-standing territorial disputes with Turkey in Cyprus and the Aegean Sea erupt into armed conflict.
Israeli and Turkish officials have repeatedly stressed that the Israel-Turkey military relationship is not aimed at any third country. Israeli Defense Minister Yitzhak Mordechai sought to defuse tensions Monday, saying that Israel would not "deal in any case with the Cyprus proble."
©1998 CBS Worldwide Corp. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press and Reuters contributed to this report