Foreign Minister Tzipi Livni expressed concern Thursday that nuclear fuel delivered to Iran by Russia may help the Islamic Republic develop a nuclear weapon of mass destruction.

The first shipment to the Russian-built Bushehr nuclear power plant in Iran was delivered last month. "The international community must turn its declarations of concern over Iran's nuclear program into action or the rules of the game are likely to change," Livni said during a visit to Moscow.

Iran has repeatedly boasted about its continuing uranium enrichment program, a step in the development of nuclear technology that can be used for domestic power – as is claimed by Iran – or to build a nuclear weapon.