"The United States is aware of it," White House spokesman Tony Snow said at a news briefing, without mentioning clear U.S. support for the tentative offer.

Instead, Snow insisted that Iran should give up its nuclear weapons program first.

"The key here is if Iran agrees to the stipulation that the United States and the international community have made, which is to back away from any potential creation of nuclear weapons, that is a development we would welcome," Snow said.

The United States has been very consistent in saying that Iran needs to renounce nuclear ambitions when it comes to nuclear weapons, Snow said.

According to reports, key European Union nations are considering adding a light-water reactor to a package of incentives in order to persuade Iran to give up its uranium enrichment program.

The United States has accused Iran of trying to develop nuclearweapons under the cover of civilian nuclear programs. However, Iran has insisted that its nuclear programs are for peaceful purposes only.