Iranian elite Revolutionary Guard soldier in the foreground at Iran's nuclear enrichment facility in Natanz, 09 Apr 2007

Iran has categorically denied claims that it is building a secret underground military nuclear facility near its existing complex at Natanz in the central part of the country.

Iranian nuclear official Javad Vaeedi issued the denial in a statement to Iranian media Friday. He said the allegations are designed to destroy what he called the "positive climate" created by Iran's cooperation on the nuclear issue.

Thursday, the opposition group National Council of Resistance of Iran said the Tehran government was building an underground facility about five kilometers from the Natanz complex.

The exile group told a news conference in Paris that the new facility would be operational in six months. The claim could not be independently verified.

The National Council of Resistance of Iran is the political arm of the People's Mujahedin of Iran, which the United States and European Union consider to be a terrorist group.

The group five years ago disclosed information about two hidden nuclear sites, including the one at Natanz, helping uncover Iran's nuclear program. However, the group has made other claims in the past that have not been verified.

Some information for this report was provided by AFP.