"Kouchner's claims are not only in contradiction with EU's macro policies on the Islamic Republic of Iran but are also aimed at questioning credibility and competency of the International Atomic Energy Agency," Foreign Ministry spokesman Mohammad-Ali Hosseini said.

Hosseini added that using "convulsive words" is contrary to the historical, cultural and civilizational dignity and position of France.

"Alignment of such words with the futile strategies of the U.S. officials indicates the influence of others' unrealistic insinuations and false information and it would not serve interests of France," Hosseini said.

In an interview on the French television station LCI late on Sunday, Kouchner said: "We must prepare for the worst ... (and) the worst is war."

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

Iran has insisted that its nuclear program is for peaceful purposes and voiced hope for talks to defuse the nuclear standoff.

The United States has never ruled out military action against Iranian targets for Tehran's suspicious nuclear programs.