JERUSALEM — Prime Minister Olmert said today that he has made no promises to Syria about a future peace agreement but made clear he is prepared to make significant concessions, telling skeptical lawmakers that “sometimes the truth is unpleasant.”

Israel and Syria announced last week that they had resumed peace talks after more than a year of indirect contacts through Turkish mediators.

The surprise announcement has raised speculation that Mr. Olmert is preparing to relinquish the Golan Heights — Syria’s central demand for any peace deal.

Israel captured the strategic plateau in the 1967 Mideast war and later annexed the area. Many Israelis are reluctant to relinquish the Golan, which overlooks northern Israel and borders the Sea of Galilee, a key source of drinking water.

Mr. Olmert told a closed parliamentary hearing on the contacts with Syria that he has made no promises to Damascus, though it is clear what each side must do. Mr. Olmert has repeatedly said Syria must end its support for Hezbollah guerrillas in Lebanon and Palestinian Arab militants for there to be peace.

“What I said was I know what you want. You know what I want. Have I sold something? Have I given up anything?” Mr. Olmert said. “Let’s sit and talk. There is nothing in writing and no other commitments, except what I have said.”

Mr. Olmert was quoted by a meeting participant who spoke on condition of anonymity because the session was closed.

While Mr. Olmert was evasive about what he would offer Syria, he noted that his predecessors have agreed to sweeping territorial concessions in previous peace efforts.

In the most recent talks, conducted by then-Prime Minister Ehud Barak, Israel reportedly offered to withdraw from the Golan, but the talks broke down because Syria wanted Israel to pull back several hundred yards more to the eastern shore of the Sea of Galilee.

“All those who held negotiations with the Syrians in the past were willing to make the most painful concessions. I know it’s hard to hear. Sometimes the truth is unpleasant,” Mr. Olmert said, according to the meeting participant.

During the sessions, three hardline lawmakers accused Mr. Olmert of preparing to give up the Golan.

“You hate peace. You don’t want peace. You’re just drawing Israel into more wars,” Mr. Olmert responded, according to the participant.

Yesterday, Mr. Olmert told his Cabinet that the talks with Syria would be kept out of the public eye.

Israel and Syria have fought three wars, their forces have clashed in Lebanon, and more recently, Syria has given support to Lebanese Hezbollah guerrillas and Palestinian Arab terrorist groups in the Gaza Strip. Israel is also concerned about Syria’s close ties to Iran.

The Israeli public opposes giving up the Golan, home to a thriving tourism and wine industry. An opinion poll last week found that only 19% of Israelis are willing to cede the entire plateau — even in exchange for peace.