JERUSALEM – Israel has determined that Iran would acquire the expertise to complete the nuclear fuel cycle by the end of 2005.

Israeli officials said that despite the suspension of Iran's uranium enrichment program, Teheran continues to conduct research and other activities meant to acquire capabilities required to develop a nuclear bomb. The officials said Iran would achieve indigenous nuclear capability within 2005.

"The question is not if the Iranians will have a nuclear bomb in 2009, 10 or 11," Israeli Foreign Minister Silvan Shalom said. "The main question is when are they going to have the knowledge to do it. We believe that in six months from today they will end all the tests and experiments they are doing to have that knowledge."

Officials said Israel has significantly revised its assessment of Iran's progress in developing nuclear weapons. Only several months ago, Iran was thought to have been blocked in nuclear weapons development amid its freeze of uranium enrichment.

But over the last three months, Israel's intelligence community has determined that Teheran – despite inspections by the International Atomic Energy Agency – did not slow down its research to complete the nuclear fuel cycle. This was meant to enable Iran to mine uranium, enrich it and produce a nuclear weapon.

"They are trying very hard to develop the nuclear bomb. This kind of extreme regime with a nuclear bomb is a nightmare, not only for us," Shalom said during a visit to London on Wednesday.

Officials said Iran's nuclear weapons capability would not necessarily translate into the production of an atomic bomb. But they said with expertise and facilities, Iran could produce enough enriched uranium for a bomb within months.

Shalom's statement was the second time a senior Israeli official warned of Iran's progress toward nuclear weapons. Two weeks ago, Defense Minister Shaul Mofaz briefed the European Union of Iran's advanced nuclear program.

The EU has reached an agreement to provide incentives to Teheran for a freeze in uranium enrichment.

For its part, Iran has acknowledged that the United States was conducting unmanned aerial vehicle missions over suspected nuclear facilities. Iran said it would shoot down U.S. military UAVs.

"We believe the United States has been spying against Iran for some time using satellites and other tools," Iranian Intelligence Minister Ali Yunesi said.