The United Nations Security Council on Friday approved a resolution that supports international efforts to seek a political solution in Syria. U.S. Secretary of State John Kerry said the process is designed to end the nation's civil war and provide a new government in Syria. Russia and the United States both approved the resolution, even though it doesn't address the major issue separating those two nations: What will happen to Syrian President Bashar al-Assad? Russia supports Assad but the United States wants him removed. Still, the accord was hailed as a major step toward bringing peace to Syria, where a civil war has killed millions and sent thousands of refugees fleeing into other nations. "It's going to be uphill," said U.N. Envoy to Syria Staffan de Mistura. "It will be complicated. But it will be possible." "This council is sending a clear message to all concerned," Kerry said. "The time is now to stop the killing in Syria and to lay the groundwork for a government the people of that battered land can support." Besides recognizing the 17-nation International Syrian Support Group's efforts in the peace process, the resolution provides a rough timeline for political change in Syria. It calls for "credible, inclusive and nonsectarian governance" within six months and "free and fair elections, pursuant to the new constitution," within 18 months. The resolution, which passed 15-0, seeks a ceasefire in Syria. Kerry said that ceasefire would not include ISIS. Kerry said some Security Council nations disagree on Assad's future but that nations involved in writing the resolution didn't want that issue to stop the peace process. Ending the war and bringing political stability to Syria go hand in hand, he said. "If the war is to end, it is imperative that the Syrian people agree on an alternative in terms of their governance," he said. Russian Foreign Minister Sergey Lavrov warned against the "demonization" of Assad, which he said happened to leaders like Moammar Gadhafi in Libya, who ended up being killed. That would not help the peace process, he said. The resolution has a schedule for changing the political situation in Syria. "We hope this process will not be protracted ad infinitum," Lavrov said. Senior State Department officials told CNN that Kerry and Lavrov led negotiations Friday to fine-tune the text of the U.N. resolution. Friday's meeting of the International Syria Support Group, or ISSG, the third in six weeks, sought to put in place a peace plan reached by ministers last month in Vienna under the umbrella of the United Nations. The resolution does three things, which internationalize efforts to seek a political solution in Syria. It endorses the 17-member ISSG as the main body dealing with the Syria peace process; validates the peace plan agreed to by the ISSG in Vienna last month, including a ceasefire between the regime and opposition in six months and talks leading to drafting a new constitution; and gives the United Nations a leading role in working with the regime and opposition on negotiating a ceasefire and drafting a constitution, which officials said is aimed at putting an international stamp on the peace process. Diplomats close to the talks said Friday that there is heated discussion among the nations in the meeting about the list of groups that will be considered terrorist groups and unable to take part in talks. But they said it was unlikely to affect passage of a U.N. resolution giving international endorsement of the peace process. "The consensus is that they won't reach consensus on the terrorist list today," one of the diplomats said.