Talks between Russia and the United States to agree a successor to an already expired nuclear disarmament treaty will resume in the second half of January, the Russian foreign minister said Tuesday.

"The negotiations will resume after the Christmas holidays. We believe that this will happen in the second half of January," Foreign Minister Sergei Lavrov said after talks with his Spanish counterpart.

Negotiators from both sides have so far failed to agree a successor to the Strategic Arms Reduction Treaty (START), signed in 1991 just before the break-up of the Soviet Union, and which expired on December 5.

Despite intense negotiations in Geneva, officials were not able to overcome before the Christmas holidays a range of disagreements on issues such as the numbers of carriers and inspections.

Some Russian media have reported the talks have hit major trouble but officials have insisted a new treaty is on the verge of being agreed and the unresolved issues are merely of a technical nature.

"A document of such volume and importance must be carefully looked at both from a legal and editorial point of view so that there are no divergences between the English and Russian texts," said Lavrov.