Britain, France and Germany have expressed their concern about Iran's plan to begin operations at a uranium conversion facility. Statements Wednesday from London, Paris and Berlin said Iran's announcement Monday about activities at its Isfahan facility sends "the wrong signal" about its willingness to suspend enrichment-related activities. The three nations have demanded an explanation from Iran.

In November, Iran announced it was suspending enrichment activities, after the International Atomic Energy Agency sought the move as a way to ease international concerns about a possible nuclear weapons program in Iran.

IAEA spokeswoman Melissa Fleming confirmed Tehran had informed the U.N. agency that it planned to start work at the Isfahan facility.

A Western diplomat says the Europeans are most likely upset that Tehran's announcement "violates the spirit" of the suspension agreement.

Britain, France and Germany have been working together since last August to resolve international concerns about Iran's nuclear program. They have pressed for a softer approach to win Iran's cooperation, particularly in the face of U.S. demands for a tougher stance.

The IAEA's board of governors will take up the Iranian issue again at a meeting in June. It could decide then to refer Iran to the U.N. Security Council for sanctions, if it deems it not in compliance with U.N. demands.