Camp David summit continues into the morning

Pace quickens in tense talks

The talks, which involve U.S. negotiators as well as aides to Barak and Arafat, have been tense at times, with one side reporting reasons for optimism while the other expressed growing doubts. In an effort to speed up progress, both sides have engaged in late-night talks the past two days.

Sources tell CNN there has been progress on minor differences, but negotiators can't agree on "core" issues such as a possible division of Jerusalem, which Israel considers its sacred capital.

Still photographs released to the press stir curiosity about how things are going. In one picture, Arafat is shown walking hand in hand with U.S. Secretary of State Madeleine Albright. In another, Barak appears grim. In still another, he grins while sitting in a room across from Clinton.

The president met twice Monday with Barak and also convened with Arafat on Monday afternoon.

Aides say Clinton wants to work to the last possible moment to try to bridge the parties' differences. He already has postponed a White House ceremony Tuesday at which he was to meet with members of the St. Louis Rams professional football team, the current Super Bowl champs.

'God, it's hard'

Although he insisted early on that all parties would not comment during the summit, Clinton broke his silence Sunday in a telephone interview with The New York Daily News.

He was blunt in his assessment: "God, it's hard," he said.

Clinton told a reporter the negotiations were among the toughest in which he had been involved as president. An agreement remained elusive, he said.

Jerusalem's fate a stumbling block

The future of Jerusalem, the fate of Palestinian refugees and the borders of a Palestinian state are among the key issues dividing Barak and Arafat.

The Palestinians want to establish their capital in east Jerusalem, but Israeli officials have been adamant that they must retain authority over all the ancient city. Jerusalem has proved among the most difficult topics for everyone so far, officials have said.

Barak reportedly has offered to give up most of the West Bank to the Palestinians if they will accept Israeli control over all of Jerusalem.

Palestinian officials, however, have insisted Arafat will accept no deal that excludes Palestinian rule over a section of the capital.