Netanyahu, who met with US Vice President Dick Cheney and a group of senators, said that the Iranian nuclear program could be stopped if the United States led a determined campaign.
Speaking to reporters in the American capital at the end of the meeting, Netanyahu said he did not think Iran's program was irreversible.
The Likud chairman met with 15 American senators, and said he was surprised by the level of their distress and worry over the developments in Iran.
'Iranians testing the water'
Netanyahu said the senators asked him about the military option. He responded by saying that it would have be a layer in addition to sanctions.
Tehran is refusing to end uranium enrichment in accordance with UN Security Council demands because it is not harmed as a result of its refusal, Netanyahu added.
He said, however, that there were cracks within the Iranian leadership and regime. If Iran understood that there was an economic price, there is a chance they would end their nuclear program, Netanyahu said, adding that up now Iran was not paying any price.
The Likud leaders stressed that Iran is not only threatening Israel.
Israel would be the first target of Iran's nuclear weapons, but not it's last, Netanyahu said.
He refused to give details about his meeting with Cheney, but said that the people he spoke with in Washington understood the danger.