"The Iranians could cross the technological line within a relatively short time, within months, before the end of the year," he told army radio.

"We have to prepare for that scenario," said Mofaz, who was speaking while on an official visit to the United States.

Israel, the Middle East's sole if undeclared nuclear power, and the United States have accused Iran of using its civilian nuclear power programme as a cover for attempting to develop an atomic bomb.

Tehran vehemently denies that, but has had three sets of UN Security Council sanctions imposed on it for refusing to stop enriching uranium.