The Annapolis peace conference is expected to take place at the end of November, but the US has not yet determined the exact date, Prime Minister Ehud Olmert announced Tuesday.
Speaking at a news conference after talks with President Shimon Peres, the prime minister said he expected the invitations to be sent "in the coming days."
Olmert said if negotiations with the Palestinians succeeded, it would be beneficial to future negotiations with Syria.
However, officials in Jerusalem cautioned that Israel was incapable of conducting negotiations with Syria that would be concurrent with a Palestinian track.
Meanwhile, Vice Premier Haim Ramon warned that Israel might have to act unilaterally if the talks failed.
"If it becomes evident that Israel does not have a partner that can bring results, there will be no choice but to take unilateral steps in Judea and Samaria as well," he said at the Sderot Conference on Tuesday.
Ramon said the issues on which the sides failed to reach an agreement should be left for the talks that are set to take place after the Annapolis conference.
"At the Annapolis summit, what we can do is form key agreements and postpone the disagreements to a later date," he said.
While Israel Beiteinu and Shas have presented a list of "red lines" to Olmert, outlining issues that they do not want raised at the summit, a number of MKs from Labor and Kadima have added their voices to the right-wing parties and made demands for the conference.
Jerusalem has emerged at the center of those demands, as MKs have insisted that Olmert not negotiate any land swap within the capital.
Opposition leader Binyamin Netanyahu, who began the "Forum for a United Jerusalem," has won over a number of coalition MKs - including Marina Solodkin (Kadima), Yisrael Hasson (Israel Beiteinu) and Yoram Marciano (Labor) - to that point of view. The forum was created following a speech given by Olmert at the Knesset last month, which loosely suggested that parts of east Jerusalem might be given to the Palestinians in a land exchange.
Next week, the coalition MKs have promised to join Netanyahu in a demonstration in Jerusalem's Old City, calling for the city to remain a "united Jewish capital."
"This opposition to certain aspects of Olmert's negotiation platform does not bode well," one Kadima MK said. "The coalition is being pulled to the left and to the right. It is not clear if it can withstand this pressure."
Meanwhile, Foreign Minister Tzipi Livni, speaking in Lisbon, said the peace conference offered a chance to find "common ground" with the Palestinians. Still, she cautioned, "Annapolis is part of a process... No less important is the day after Annapolis."
Livni, who made the comments at the end of a meeting of European Union and Middle East foreign ministers, also praised the Palestinians for making "the right steps on the ground" - an apparent reference to security measures taken by Palestinian Authority President Mahmoud Abbas.
She also urged Arab states to "support the moderate Palestinians."
"We expect them to support the process, to support any compromise the Palestinians need to take in order to achieve peace with Israel, and not to dictate the outcome of this kind of process," Livni said.
PA Foreign Minister Riad Malki, who held discussions with Livni on the sidelines of the Lisbon gathering, had no immediate reaction to her comments.
Livni told her Egyptian counterpart, Ahmed Abdul Gheit, that Gaza has become "a real regional problem, and there is a need for a determined effort to stop weapons smuggling into the Strip."
She updated Gheit on the latest negotiations with the Palestinians. She also held separate discussions with the foreign ministers of Jordan and Mauritania.
In her address to the assembled foreign ministers, Livni said the core issues would be tackled in the post-Annapolis negotiations. She called for compromise accompanied by actions on the ground.
Livni said the creation of a Palestinian state depended on Israel's ability to "hand the keys" to a responsible party that could take control and ensure that another terrorist state would not be established next to Israel.
EU Commissioner for External Relations Benita Ferrero-Waldner told the closed-door meeting she hoped the world was "on the brink of making progress toward settling this terrible, long-standing conflict," according to a transcript of her remarks.
She acknowledged that there was a long way to go before peace could be achieved, but "a journey of 1,000 miles begins with the first step," she said, quoting an Asian proverb.
Ferrero-Waldner said there was a sense that the major world powers were truly committed this time to finding peace.
"Everybody wants to make it work," she said.
Luxembourg Foreign Minister Jean Asselborn added his weight to that sentiment, saying: "All the countries represented here want to bring this process to a conclusion. Everyone agrees we're at an important moment."