Reports from South Korea say an uncle of North Korean leader Kim Jong-un has been removed from his post.
Chang Song-thaek, 67, lost his position as vice-chairman of the North's top military body and one of the most powerful politicians in North Korea.
Two close aides were also executed for corruption in late November, according to the reports.
If confirmed, the BBC says Mr Chang's removal would be the biggest upheaval in North Korea's leadership since Mr Kim took over after Kim Jong-il died in 2011.
The Yonhap news agency said the information was from a briefing by the National Intelligence Service, based on information provided by multiple sources.
Mr Chang is married to Kim Jong-il's sister. He was elected to the Central Committee of the Korean Workers' Party in 1992.
He was often pictured beside his son Kim Jong-un and was seen by some observers as the power behind him.
He was regarded as an economic reformer and a major influence on Kim Jong-un.
He held key positions in both the KWP and the National Defence Commission.