Teheran is ready for nuclear talks with the West without preconditions, a senior Iranian nuclear official was quoted by state television as saying on Tuesday.

"Talks without preconditions is Iran's main stance in negotiations on the nuclear issue," Iran's envoy to the UN nuclear agency watchdog, Ali Asghar Soltanieh, was quoted as saying, according to a Reuters translation.

The Iranian television report added that Soltanieh had made the announcement based on "mutual respect" for the West.

The Reuters report noted that Iran had made similar statements in the past.

In the most recent assessment, meanwhile, US State Department officials estimated that Iran would be unable to develop a nuclear weapon in the next four years, despite previous assessments.

The State Department cited a recently disclosed congressional document.