The taking of the U.S. Embassy in Tehran in 1979 put the two countries on a 30-year course of confrontation and mistrust, U.S. President Barack Obama said.

More than four dozen American embassy workers were held hostage for 444 days after Iranian students stormed the U.S. Embassy, which marked the overthrow of Shah Mohammad Reza Pahlavi and the rise of Ayatollah Ruhollah Khomeini.

"This event helped set the United States and Iran on a path of sustained suspicion, mistrust, and confrontation," Obama said in a statement Wednesday.

He repeated earlier statements that the United States wants to move forward and seek a diplomatic relationship with Iran "based upon mutual interests and mutual respect."

"We have made clear that if Iran lives up to the obligations that every nation has, it will have a path to a more prosperous and productive relationship with the international community," Obama said.

The ball now is in Iran's court, he said.

"We have heard for 30 years what the Iranian government is against," Obama said. "(The) question, now, is what kind of future it is for. ... It is time for the Iranian government to decide whether it wants to focus on the past, or whether it will make the choices that will open the door to greater opportunity, prosperity, and justice for its people."