He told NBC he believed Israel had not yet decided how to deal with the issue, amid reports that Israel may strike Iran as early as spring.
Mr Obama said the aim was to resolve the crisis diplomatically, but added that no option was off the table.
The US and Israel suspect that Iran is building a nuclear bomb. Iran says its programmes are for peaceful purposes.
Last November, the UN nuclear watchdog, the IAEA, said it had information suggesting Iran had carried out tests “relevant to the development of a nuclear explosive device”.
Since then, the US and the EU have imposed a series of sanctions against Iran, including measures targeting the country’s lucrative oil industry.
“I’ve been very clear - we’re going to do everything we can to prevent Iran from getting a nuclear weapon and creating a nuclear arms race in a volatile region,” Mr Obama told NBC in a live interview on Sunday.
He said Washington was working “in lockstep” with Israel, which was right to be very concerned about Iran’s controversial activities.
Asked if he believed the Jewish state could launch a pre-emptive strike against Iran, Mr Obama said: “I don’t think Israel has made a decision on what they need to do.”
He declined to answer directly a question whether Washington would be consulted first, saying only that the US and Israel “have closer military and intelligence consultation… than we’ve ever had”.
Mr Obama also said there was no evidence that the Iranians had “intentions or capabilities” to strike US targets in retaliation.
The US leader was eager to play down tensions between the US and Israel over suggestions that Israel is preparing a military strike against Iran, the BBC’s Jane Little in Washington reports.
But she says that behind the scenes Washington is deeply alarmed by reports that Israel may strike Iran as early as April - in a move that would drive up tensions in the Middle East as well as oil prices, which would threaten the global economy and Mr Obama’s re-election chances.
February 6, 2012
US and Israel 'in unison' on Iran, says Obama
RSS feed: http://defterisk.tumblr.com/rss