Officials from Russia and the United States resumed arms treaty negotiations on Monday in Geneva.

The talks aim to update a bilateral agreement called the Strategic Arms Reduction Treaty (START), which expired in December.

Gareth Evans, co-chair of the International Commission on Nuclear Non-Proliferation and Disarmament, told reporters in Geneva on Monday that a new version of the treaty is "on the verge of happening," and described the remaining issues as insubstantial.

Evans, who on Monday released a report on nuclear disarmament called Eliminating Nuclear Threats, said that the "most crucial of all years is this year." In addition to the START negotiations, several international conferences will take place this spring, such as U.S. President Barack Obama's Nuclear Security Summit in April and the Nuclear Non-Proliferation Treaty Review Conference in May.

Evans also called on the United Nations Conference on Disarmament (CD) to bring ratification of the Comprehensive Nuclear Test Ban Treaty (CTBT) to the General Assembly.

"Make an explicit resolution creating specific negotiations mandated for a specially constructed diplomatic conference," Evans advised the CD.

Created in 1996, the CTBT has been ratified by 151 states, signed but not ratified by 32 states, and neither signed nor ratified by three countries -- India, Pakistan and North Korea.