A draft resolution on Iran's nuclear program is expected to be ready tomorrow.
After more than two weeks of talks, the six negotiators tonight said they were close to agreement on a text to be put to the full 15-member UN Security Council.
Russia's UN ambassador, Vitaly Churkin, told reporters he had received "very positive" instructions from Moscow.
But China's UN ambassador, Wang Guangya, said agreement had not been reached on Iranian officials and organisations subject to financial sanctions, including firms controlled by Iran's Revolutionary Guard.
Also expected in the text are a ban on government loans to Tehran and an embargo on conventional weapons Iran could export.
"We will have consultations on Iran tomorrow when they will give us a draft of whatever they have in hand, whether it is agreed or not agreed," South African Ambassador Dumisani Kumalo, this month's council president, said.
The five permanent council members with veto power - the United States, Britain, France, Russia and China - are negotiating a text along with Germany, which holds the current presidency of the European Union.
The US and leading European countries suspect Iran is seeking to build nuclear weapons under the cover of a civilian atomic program.
Tehran denies the charge and says its program is for generating electricity only.
The new resolution is a follow-up to one adopted by the Security Council on December 23rd that imposed trade sanctions on sensitive nuclear materials and technology and froze assets of key Iranian individuals, groups and businesses.