Kerry rules out further extension of nuclear talks with Iran

US Secretary of State John F Kerry said in an interview from Munich broadcast on Sunday that it would be ''impossible'' to extend nuclear negotiations with Iran if an agreement on fundamental principles is not reached in the coming weeks.

Using more categorical language than he has employed previously, Kerry definitively precluded a third extension to talks with Iran about reducing its ability to make a nuclear bomb or a consequent easing of sanctions.

In November, when no deal could be struck by a self-imposed deadline, a temporary agreement, which had been in place for a year and had been extended once before, was pushed to late June. Kerry said at the time that the major points of agreement would have to be reached by late March.

In an interview with NBC's `Meet the Press,' taped on Saturday in Munich where he was attending an international security conference, Kerry appeared to close the door on another extension.

''Well, the only chance I can see of an extension at this point in time would be that you really have the outlines of the agreement,'' he said. ''You understand exactly what you're doing.''

One reason for an extension, Kerry added, would be to flesh out complex details spelt out in numerous footnotes known as 'annexes'.

''But if we're not able to make the fundamental decisions that have to be made over the course of the next weeks, literally, I think it would be impossible to extend,'' he said. ''I don't think we would want to extend at that point. Either you make the decisions to prove your program is a peaceful one, or if you're unable to do that, it may tell a story that none of us want to hear.''

The nuclear talks, which began a decade ago with Iran and were revived after Hassan Rouhani, a moderate, was elected president in 2013, have been the subject of much concern. Israeli President Benjamin Netanyahu, who has reached out to the foreign ministers of the five other countries that are negotiating partners of the United States to lobby against a deal, is expected to be highly critical of any potential agreement in an address to Congress planned for 3 March.