The US has reported progress in talks with major powers on imposing further sanctions against Iran over its refusal to halt uranium enrichment.
The UN nuclear watchdog says Iran is continuing uranium enrichment
US state department officials said most of the issues had been resolved during a conference call between the US, UK, Germany, China, Russia and France.
Ambassadors could start drafting a new UN resolution next week, they said.
The UN nuclear watchdog confirmed last week that Iran had ignored a deadline to suspend nuclear activities.
Thursday's telephone conference call followed talks between diplomats from the six key nations in London earlier in the week.
"They had a good productive discussion during which they made progress in agreeing on the elements of a resolution," the US state department said in a statement.
POSSIBLE NEXT STEPS
New UN resolution on tougher economic sanctions, tabled by US or European allies
US pressure on Europeans to step up bilateral sanctions
New initiative to get Iran back to talks
The countries have agreed to hold a further conference call on Saturday and their UN ambassadors "could begin drafting the text of a resolution next week".
New tougher sanctions could include travel bans on Iranian officials individuals associated with nuclear and missile programmes.
Iranian President Mahmoud Ahmadinejad has said his country will not go back on its nuclear programme.
Iran denies Western claims it is secretly trying to build nuclear arms, saying its nuclear programme is for peaceful, energy-producing purposes.
The UN Security Council imposed sanctions on Iran in December, setting a 60-day deadline for it to stop enriching uranium.
But a report last week by the International Atomic Energy Agency (IAEA) said that Iran was instead expanding the programme.
Enriched uranium is used as fuel for nuclear reactors, but highly enriched uranium can be used to make nuclear bombs.