The United States and Russia say they have completed most of the technical discussions on reaching an agreement in principle on a ceasefire in Syria and are now focused on "making the cessation of hostilies real".

"I think in the nearest time we will present the fruits of our joint efforts," Russian Foreign Minister Sergei Lavrov said.

Lavrov made the comments at a joint press conference with US Secretary of State John Kerry following negotiations in Geneva, Switzerland.

The top US and Russian diplomats make clear they have yet to overcome differences on a Syrian ceasefire plan, but both Kerry and Lavrov say a solution is very near.

They also indicate that separating US-backed rebels from the al-Qaeda-linked al-Nusra front has been one of the sticking points in the talks.

- dpa