Peace talks between Israel and Syria began here with both sides pledging to work hard for a final settlement.
However, the Israeli Prime Minister, Mr Ehud Barak, and the Syrian Foreign Minister, Mr Faruq al-Shara, ignored photographers' requests to shake hands.
President Clinton relaunched the negotiations, which have dragged on over eight years, in the Rose Garden of the White House, flanked by Mr Barak and Mr Shara.
This is the first time Israel and Syria have been represented at such a senior level and it encouraged hopes that both sides intend the talks to succeed.
After the opening ceremony, Mr Clinton separately met Mr Barak and Mr Shara, who then crossed the street to continue the negotiations in Blair House.
This phase of the talks is expected to end today with the setting of a date and place for the next phase.
Mr Clinton, who was clearly pleased that he had brought the two sides together for the first time since the Israeli-Syrian talks broke off in 1996, cautioned that "what we are witnessing today is not yet peace, and getting there will require bold thinking and hard choices".
Success was "not guaranteed" and "there will be challenges along the way, but we have never had such an extraordinary opportunity to reach a comprehensive settlement", the President said.
He then asked Mr Barak and Mr Shara to make brief remarks but told the journalists that they would not be allowed to ask questions.
Mr Barak said Israel had come here "to put behind us the horrors of war and to step forward towards peace".
He said Israel was fully aware of the opportunity and serious efforts that would be needed "in order to begin this march together with our Syrian partners to make a different Middle East where nations living side by side in peaceful relationship and in mutual respect and good neighbourliness".
Mr Shara, who spoke for considerably longer, struck a tougher note insisting that "peace for Syria means the return of all its occupied land" but added that "for Israel, peace will mean the end of the psychological fear which the Israelis have been living in as a result of the existence of occupation which is undoubtedly the source of all adversities and wars".
Mr Shara said the vision and sufferings of Arabs had been "to tally ignored" over the past 50 years due to lack of opportunity to convey them to international opinion. The most recent example of this was "the last four days of attempts to muster international sympathy with a few thousand settlers in the Golan, ignoring totally more than half a million Syrian people who were up rooted from tens of villages on the Golan."
Mr Shara concluded on a hopeful note. "We all here agree that we are at a threshold of a historic opportunity, an opportunity for the Arabs and Israelis alike, and for the United States and the world at large."
A Senior Israeli official said Mr Ehud Barak's delegation "was astonished" by the speech in which Mr Shara suggested that Israel provoked the 1967 war.