WikiLeaks is said to be preparing a release that will allege Swedish foreign minister Carl Bildt has been a US informant since the 1970s.
The news was broken by Swedish newspaper Expressen, who have access to an internal Wikileaks memo. The memo says that the allegations are supposedly based on a US diplomat's report, and will be politically explosive. "He will be forced to resign", one source told the paper.
"There are secret documents that reveal that Bildt cooperated with the U.S. administration in a manner contrary to Swedish law", one source told Expressen.