"The two sides expressed an overall positive assessment of real progress in achieving a truce on Syrian soil, which is generally respected and has already led to a sharp decrease in the level of violence," the Russian foreign ministry said in a statement.
Lavrov and Kerry, on a phone call, stressed the need to prevent delay of intra-Syrian talks under the UN auspices, as well as to provide humanitarian aid to blocked areas in Syria, reports Xinhua.
"It is essential to ensure from the very beginning the participation (in the intra-Syrian negotiations), along with the delegation of the Syrian government, of a wide spectrum of all opposition forces, including Syrian Kurds," the ministry quoted Lavrov as saying.
The top diplomats confirmed that joint efforts would be paid by both countries' representatives in Geneva to ensure smooth work of the International Syria Support Group (ISSG) task forces on humanitarian and ceasefire issues.
Lavrov and Kerry discussed a schedule of political contacts for the nearest future.
They also agreed to continue cooperate with all involved parties in order to find the ways to settle Yemeni conflict through political dialogue.
The Russia-US-backed cessation of hostilities plan has gone into effect at midnight last Friday in all Syrian cities. The truce has so far been largely adhered to despite sporadic violations.
Currently, a UN-mediated intra-Syrian talk was scheduled for March 9 in Geneva as a fresh diplomatic effort to politically settle the Syria crisis.