Unveiling the plan to end the island-nation's 30 years of partition, UN Secretary-General Kofi Annan on Wednesday urged Cypriots to approve it.
"This is a moment of high drama," Annan said.
"There have been too many missed opportunities in the past. I urge you not to make this mistake again," he added, urging Turkish and Greek Cypriots to vote in favour of the plan.
A US official said Greece, Turkey, Greek Cypriot and Turkish Cypriot leaders had endorsed the plan at the end of a week of tensed talks at a Swiss alpine resort. It raises the possibility of a united Cyprus entering the European Union on 1 May.
"There have been too many missed opportunities in the past. I urge you not to make this mistake again"
Both Greek and Turkish Cypriots must approve the plan, forming a loose union of two ethnically-based zones.
The island had been partitioned into a Turkey Cypriot north, recognized only by Ankara, and a Greek south since Turkish troops invaded 30 years ago in response to a coup by militant Greek Cypriots.
"The chance for peace is between this settlement or no settlement," Annan said. "This plan is fair and is designed to work."
The poorer Turkish Cypriot minority had been seeking and appeared to have found stronger reassurances on the number of Greeks who would be allowed to settle in their northern part of the island.
US Secretary of State Colin Powell described the moment as a 'historic opportunity."
"This is a time for leaders to show flexibility, for leaders to be ready to compromise for the greater good of the Cypriot people," he said.
About two-thirds of Cyprus's 800,000 population are Greek Cypriots who are far wealthier than Turkish Cypriots who control only one-third of the territory in the north.