German media report the U.S. National Security Agency spied on former German Chancellor Gerhard Schroeder from 2002 because of his opposition to the U.S.-led invasion of Iraq.
The German newspaper "Sueddeutsche Zeitung" said its report was based on U.S. government sources and an NSA insider.
It follows revelations last year in the German media that current Chancellor Angela Merkel's cell phone had been targeted by the NSA.
The reports then were based on leaks from the former NSA intelligence contractor Edward Snowden.
He told German TV in January that the NSA also spied on German industry, such as engineering firm Siemens.
Snowden has claimed asylum in Russia but has offered to go to Berlin to help a Bundestag probe into NSA activities.
Based on reporting by Reuters, AP, and dpa