The Foreign Ministry expressed regret Wednesday over Tehran's nuclear defiance.

"It is extremely regrettable that Iran restarted uranium enrichment activities despite calls (not to do so) from the international community, including Japan," Yoshinori Katori, the ministry's press secretary, said at a news conference.

"Japan strongly hopes that Iran will seriously take to heart the International Atomic Energy Agency board of governors' resolution," he said, referring to the IAEA's Feb. 4 decision to report Iran to the U.N. Security Council for noncompliance with its obligations under the IAEA safeguards accord.

Katori said Japan hopes to use the visit by Iranian Foreign Minister Manouchehr Mottaki later this month to reiterate its appeal to Tehran to halt its uranium enrichment activities.

On Tuesday, the deputy secretary of Iran's Supreme National Council, Javad Vaeidi, told reporters in Tehran that enrichment of uranium resumed on a small scale last week at the country's main enrichment plant in Natanz.