Negotiations between the government of President Bashar al-Assad and members of the Syrian opposition are scheduled to start next week, the first step in a U.N.-backed 18-month timeline for political change in Syria. But divisions over who will represent the Syrian opposition may force the U.N. to postpone the talks.
Russia and Iran, which support Assad, are at odds with the U.S., Saudi Arabia, Gulf nations and Europe over which groups are legitimate, and which are considered terrorists and should be excluded from the negotiations.
The major power brokers in the conflict are also at odds over the future role Assad could play in a political transition. The U.S. and its European and Arab allies say he has no role in Syria's future, but Russia and Iran argue that the Syrian people should decide Assad's fate.
Kerry and Lavrov met in Zurich to hash out the issue before flying by helicopter to the Swiss ski resort town of Davos to take part in the World Economic Forum.
The State Department said Kerry and Lavrov discussed "the importance of maintaining progress toward a diplomatic solution to the crisis" in Syria and plans for the peace talks, which U.N. Special Envoy for Syria Staffan de Mistura, has slated to convene in Geneva on Jan. 25.
U.N. officials said this week de Mistura would not issue invitations for Monday's talks until the key countries involved reached agreement on a list of who would comprise the Syrian opposition delegation for the talks.
Both the U.S. and Russia have said they want the talks to start as scheduled on Monday, but it did not appear Kerry and Lavrov made any breakthroughs in their three-hour meeting.
"We do not have any kind of thoughts about changing the beginning of the talks from January to February," Lavrov told reporters. "This is the position of Russia and the USA."
"The political process will begin, we hope, in the nearest future, during January," he said. "Various dates have been named, but the final decision will be taken by the secretary-general of the United Nations on the advice and recommendations of his special envoy, Staffan de Mistura."
Lavrov said the focus of the talks with Kerry was "coordination" about terrorist organizations that should be banned from negotiations as well as a ceasefire, which is called for in the U.N.-backed plan once the talks begin.
State Department spokesman John Kirby said Kerry urged Russia to use its influence with Assad "to ensure immediate, unimpeded and sustained humanitarian access to all Syrians in need," particularly in Madaya, where aid workers have reported deaths due to starvation.
The U.N. has accused the government of blocking aid to Syrians in rebel-held areas. In Davos on Wednesday, U.N. Secretary-General Ban Ki-moon said 400,000 Syrians are trapped in besieged communities.
Kerry and Lavrov also discussed ways to push forward the peace process between the government and Russian-backed rebels in Ukraine and international efforts to respond to North Korea's nuclear test earlier this month, Kirby said.
Kerry arrives in Switzerland on the heels of the implementation of the Iran nuclear agreement and a prisoner swap between the U.S. and Iran that saw the release of five Americans, including Washington Post reporter Jason Rezaian.
In Davos he will meet Israeli Prime Minister Benjamin Netanyahu, a vocal critical of the nuclear deal, and Iraq's prime minister.
This weekend Kerry will visit Riyadh for consultations with Saudi leaders and attend a meeting of Gulf ministers. Kerry will seek to assure nervous Gulf allies that the U.S. will not abandon them despite Washington's warming ties with Iran.
From the Middle East, Kerry will travel to Asia for meetings in Laos, Cambodia and China, where concerns over North Korea will top the agenda.