Envoys from the six countries -- France, Britain, Germany, Russia, China and the United States -- were still unable to agree on a draft UN resolution on Tuesday after concluding another round of informal meetings.

The draft, sponsored by Britain, France and Germany, would slap a ban on imports and exports of materials and technology relating to uranium enrichment, reprocessing and heavy-water reactors, as well as ballistic missile delivery systems.

The lack of progress was largely due to Russia's opposition to a travel ban on Iranian officials and firms associated with the nuclear program, as well as to a list of some Iranians subject to an assets freeze, UN diplomats said.

In an earlier resolution, the 15-nation UN Security Council required Iran to suspend its uranium enrichment by Aug. 31. But Iran ignored the deadline.

The United States has been seeking to impose sanctions on Iran through the UN Security Council on the grounds that Iran is developing a nuclear weapon program under the cover of a civilian program.

Iran has said its nuclear program is for peaceful purposes only.

Source: Xinhua