Obama's statement was made during an interview with CNN.
Earlier Tuesday, Obama said that if Iran's nuclear ambitions were curbed, the US would have no need to deploy anti missile systems in Europe.
Obama's statement followed one by US Vice President Joe Biden, who said that Israel was free to decide on a strike. Biden was asked about the matter three times by ABC Television, and replied that "(Israel is) entitled to do that. Any sovereign nation is entitled to do that. But there is no pressure from any nation that's going to alter our behavior as to how to proceed. "
However, the vice president did add that "what we believe (pursuing diplomatic options regarding Iran) is in the national interest of the United States, which we, coincidentally, believe is also in the interest of Israel and the whole world. And so there are separate issues.
Following Biden's statement, the White House was forced to issue a clarification to the contrary. State Department spokesman Ian Kelly added that while no military action was given the go-ahead, Washington has no intention of "dictating Israel's actions."
The Washington Times quoted anonymous Israeli sources Tuesday, as saying that Prime Minister Benjamin Netanyahu did not ask for the US permission on an Iranian strike, fearing he would meet a refusal.
AFP contributed to this report