U.S. Offers to Sell Warplanes; Rabin Unsure Israel Can Pay : Mideast: Prime minister cites $1.8-billion price for F-15E fighters. U.S. has said it will not boost its aid.

The Clinton Administration announced Monday that it has offered to sell Israel 20 top-of-the-line F-15E warplanes, but visiting Prime Minister Yitzhak Rabin said he is uncertain whether his government can afford the $1.8-billion price tag.

Rabin and Defense Secretary Les Aspin discussed the proposed sale during a three-hour meeting at the Pentagon. The prime minister, who conferred with President Clinton on Friday, is scheduled to leave today for Canada to continue his North American trip.

“There are some technical things that need to be worked out, and we are working on those,” Aspin told reporters with Rabin at his side.

“We have to study the problems of cost, the cash flow,” Rabin added.

The U.S. government has financed most of Israel’s major weapons purchases in the past, either as outright grants or through loans ultimately repaid from later U.S. foreign aid programs. But faced with severe budgetary problems at home, the Administration has made it clear that it will not increase Israel’s usual allocation of $3 billion a year in military and economic aid, already the highest aid program for any country.

The F-15E, built by McDonnell Douglas Corp., is the U.S. Air Force’s premier fighter-bomber. Washington has never sold the plane abroad, although a number of countries--including Israel--have earlier models.

The Administration offered the aircraft sale as part of a package of measures intended to reward Israel for signing a peace agreement with the Palestine Liberation Organization and to give Rabin tangible benefits to show the Israeli public. Despite the high hopes engendered by Rabin’s handshake with PLO Chairman Yasser Arafat, the pact has lost much of its initial popularity among Israelis because it has failed to stop Palestinian attacks against Israeli civilians.

Meanwhile, State Department spokesman Mike McCurry announced that Secretary of State Warren Christopher will visit the Middle East early next month in an effort to get the Israel-PLO peace talks back on track. Christopher also plans to shuttle between Jerusalem and Damascus to revive the Israel-Syria peace process.

Late Monday, Christopher and Rabin met for a little more than an hour to discuss Christopher’s upcoming visit to the region, officials on both sides said. “They focused on next steps,” a State Department official said.

Appearing on public television’s “MacNeil/Lehrer Newshour,” Rabin said Syria so far has rejected Israeli proposals for secret meetings in addition to the semipublic negotiations conducted in Washington.

In Damascus, Syrian officials said Clinton has assured Syria that the United States wants a comprehensive Middle East peace that would involve Syria, Jordan and Lebanon in addition to the PLO.