Israeli Prime Minister Benjamin Netanyahu was prepared to hand back the occupied Golan Heights to Syria in return for peace, Israel's largest-selling newspaper reported on today.
Mr Netanyahu's secret peace contacts with Syria began in 2010 but they ended after the Syrian uprising began last year.
Rumours about back-channel diplomacy conducted by US mediator George Mitchell have been flying around for two years, but the full extent of Mr Netanyahu's peace offer will come as a shock to his supporters.
In public, he has always backed Israel's 1981 annexation of the Golan Heights and excoriated former Prime Minister Ehud Barak for reportedly offering to return the strategic plateau to President Bashar Assad's father in US-sponsored peace talks in 2000.
But according to the plan published on Friday in Yedioth Ahronoth, Mr Netanyahu surprised US officials by agreeing to withdraw to the pre-June 1967 border, inviting Syria to regain control of the towering mountain ridge and return to the eastern shore of the Sea of Galilee.
In return, the two states would exchange ambassadors, end the state of war and establish full relations. Syria wanted the process completed within two years. Israel asked for a longer timetable.
The map, taken by a US mediator to Damascus in September 2010, was based on a proposal first outlined by Mr Netanyahu to President Barack Obama over a one-on-one meeting and working lunch at the White House in July that year.
Veteran diplomatic correspondent Shimon Schiffer reported that the contacts, carried out by former marines commander Fred Hoff, a military mapping expert on Mr Mitchell's staff, were conducted under an "unusual" veil of secrecy. Mr Hoff left his post as special US envoy to the Middle East earlier this week.
Mr Hoff's notes, quoted by the paper, said meetings were held in Mr Netanyahu's private residences in Jerusalem and Caesaria, but not at his office.
"According to the documents, the negotiations between the sides were based on consent to a full withdrawal from the Golan Heights and transferring them to Syrian sovereignty, in return for a full peace agreement including an exchange of embassies," the paper reported.
"A senior source in the US administration said a few days ago that the negotiations had been serious and far-reaching, and it could be presumed that if not for the Syrian civil war they would have ended in an agreement," the paper added.
In a carefully-worded statement, Mr Netanyahu's office said: "This initiative was one of many proposed to Israel over the past few years. At no point did Israel accept this American initiative. The initiative is irrelevant, and its publication at this time stems from political considerations."
Mr Netanyahu has also disavowed peace contacts with Syria during his first term as prime minister conducted by the American businessman Ronald Lauder.