Lavrov made the comments in Switzerland on Wednesday, where he was planned to talk with US Secretary of State John Kerry to resolve differences on who is eligible to join UN-mediated peace talks for Syria.
Russia and Iran, which back Syrian President Bashar Assad, have severe differences with Saudi Arabia, other Arab states, the United States and Europe over which "opposition" groups should be considered terrorists and not allowed to be part of an 18-month political transition process that the UN has endorsed.
One dispute is over the groups Ahrar-as-Sham and Jaish al-Islam, which Russia and Syria consider terrorists but Saudi Arabia, the United States and others view as legitimate opposition groups.
The dispute is threatening to delay the planned Jan. 25 start of UN-meditated peace talks, according to the Associated Press.
"We're not unmindful of the fact that there still remains differences of opinion, and that this is a complicated process and that there is still quite a bit of work that needs to be done to get the meeting to occur," State Department spokesman John Kirby said Tuesday. "But it's our hope that this can continue to move forward, and that we can have this meeting on the 25th."
UN officials say they remain focused on starting the talks on Jan. 25 as planned, but they say they can't send out invitations until the key countries agree on an opposition list and have hinted at a possible delay.