UNITED NATIONS: UN leader Ban Ki-moon on Wednesday expressed regret at the failure to make progress at nuclear talks between Iran and the main international powers and called for a new “intensity” of efforts to avoid a showdown.

Ban “regrets” that Iran's talks with Britain, China, France, Germany, Russia and United States “were unable to reach agreement on concrete and reciprocal measures at their meeting in Moscow,” his spokesman Martin Nesirky said.

The Moscow meeting on Tuesday produced only an accord to hold new technical and political talks on accusations by the United States and its allies that Iran seeks to develop a nuclear bomb. Iran denies the charge.

The UN secretary general hopes that “the parties strengthen their resolve to quickly achieve a negotiated solution that restores international confidence in an Iranian nuclear program that could be deemed exclusively peaceful.”

He appealed to both sides “to resume their diplomatic engagement with renewed intensity and with the utmost flexibility.”

The talks have been held amid speculation that Israel or the United States could launch a military strike against Iran's nuclear facilities.