The United States considered using nuclear weapons against Afghanistan in response to the September 11 attacks, Der Spiegel reported on its website Saturday.

Michael Steiner, who served as a political advisor to then-German Chancellor Gerhard Schroder, told the German daily that the nuclear option was one of the possibilities examined after the attacks.

"The papers were written," Steiner said when asked whether the U.S. was considered using nuclear weapons in response to the attacks orchestrated by Al-Qaida's Osama bin Laden, in which almost 3,000 people were killed. "They had really played through all possibilities."

Steiner added that Schroder had feared that the U.S., which was in a state of shock following the attacks, would overreact.

Moreover, Steiner said in the interview that Schroder rejected his idea to publish a statement declaring "unconditional support" for the United States.

Tensions between Schroder and U.S. President George Bush intensified in 2003 when the chancellor refused to join U.S.-led coalition in the military campaign against Iraq.