UNITED NATIONS - U.N. Security Council members unanimously approved a U.N. resolution Friday endorsing a peace process for Syria including a cease-fire and talks between the Damascus government and the opposition, but the draft makes no mention of the most contentious issue - the future role of Syrian President Bashar al-Assad.

The resolution makes clear that the blueprint it endorses will not end the conflict, deep into its fifth year with well over 300,000 killed, because "terrorist groups," including the Islamic State group and the al-Qaida-linked al-Nusra Front, are not part of the cease-fire.

U.S. Secretary of State John Kerry praised "the unprecedented degree of unity" in the council, which has been stymied in the past over a political solution in Syria, and called the resolution "a milestone."

Foreign ministers from 17 countries met for more than five hours on how to implement their call in Vienna last month for a cease-fire and the start of negotiations between the government and opposition in early January. At the same time, diplomats worked to overcome divisions on the text of the resolution.

The resulting agreement "gives the Syrian people a real choice, not between Assad and Daesh, but between war and peace," Kerry said, using the Arabic acronym for the Islamic State extremists.

"We're under no illusions about the obstacles that exist . . . especially about the future of President Assad," where "sharp differences" remain, Kerry said.

But he made clear that Assad must go if there is to be peace.

"Assad has lost the ability . . . to unite the country," Kerry said. "If the war is to end, it is imperative that the Syrian people have to agree on an alternative" to their government.

Secretary-General Ban Ki-moon said Syria was "in ruins," singling out besieged areas where "thousands of people have been forced to live on grass and weeds," which he called "outrageous."

"This marks a very important step on which we must build," Ban said of Friday's resolution.

Ministers said they would meet again in January.

The resolution calls on the secretary-general to convene representatives of the Syrian government and opposition "to engage in formal negotiations on a political transition process on an urgent basis, with a target of early January 2016 for the initiation of talks."

Within six months, the process should establish "credible, inclusive, and nonsectarian governance," and set a schedule for drafting a new constitution. U.N.-supervised "free and fair elections" are to be held within 18 months under the new constitution.

The resolution calls the transition Syrian-led and Syrian-owned, stressing that the "Syrian people will decide the future of Syria."