In an interview published Friday, Netanyahu hinted Israel may have to strike Iran even without U.S. support to prevent Tehran from building a nuclear weapon.
The comments indicate Netanyahu is not backing down from his thinly-veiled criticism of the Obama administration, despite a phone call from the U.S. president this week that was meant to smooth over their differences.
In the interview in Israel Hayom, a daily that is a staunch backer of the premier, Netanyahu says he has heard those "who say we should wait until the last minute."
Then, he asks: "But what if the U.S. doesn't act?"
Iran denies it is seeking a nuclear bomb.