"The chancellor has expressed the view that there is no military option," Ulrich Wilhelm said, adding that "the door for negotiations remains open."

The U.S. leaders have said repeatedly any option would not be ruled out in dealing with Iran's nuclear program as they insist that Iran is developing nuclear weapons.

But Iran has said its program is for peaceful purpose, refusing to comply with a UN directive that it cease uranium enrichment by Aug. 31.

Senior diplomats from Britain, France and Germany will meet their counterparts from the United States, Russia and China in Berlin on Thursday to discuss the Iranian nuclear crisis.

European Union chief diplomat Javier Solana is expected to hold talks with Iranian negotiators this week.