President Barack Obama has warned that the United States will not hesitate to use force to prevent Iran from obtaining nuclear weapons.
But the president says diplomacy is still the preferred course of action.
Mr Obama was speaking on Sunday at the American - Israel Public Affairs Committee, where Israeli President Shimon Peres earlier said Iran is a danger to the entire world.
However Mr Obama warned against speculation about the use of military power against Iran.
"I firmly believe that an opportunity remains for diplomacy - backed by pressure - to succeed," he said.
"I would ask that we all remember the weightiness of these issues, the stakes involved for Israel, for America, and for the world. Already, there is too much loose talk of war," Mr Obama said.