Image copyright Reuters Image caption Many observers saw Mr Chang as having a major influence on Kim Jong-un

North Korean state TV is reported to have removed footage of a powerful uncle and key aide to leader Kim Jong-un from a documentary, following reports that he has been dismissed.

South Korean news agency Yonhap said the original film about Mr Kim had already been broadcast nine times.

But when it aired again on Saturday, images of his uncle Chang Song-thaek, had been edited out, Yonhap reports.

On Tuesday South Korean intelligence said Mr Jang, 67, had been removed.

He had held senior posts in the ruling communist Korean Workers' Party and the National Defence Commission, the North's top military body.

Intelligence officials also said two of his close aides appeared to have been executed for corruption.

Chang Song-thaek Born 1946; marries Kim Jong-il's sister in 1972

Joins Korean Workers' Party administrative ranks in 1970s

Elected to Central Committee in 1992

Sidelined in 2004, but rehabilitated in 2006

2011: Gets top military post under Kim Jong-un

Nov 2013: Reportedly dismissed Profile: Chang Song-thaek Secretive 'first family'

The National Intelligence Service (NIS) said it has made the assessment based on information provided by multiple sources.

If confirmed, Mr Chang's removal would be the biggest upheaval in North Korea's leadership since Mr Kim succeeded his father, analysts say.

Kim Jong-un took over after Kim Jong-il died in 2011. Mr Chang is married to the elder Kim's sister.

He has often been pictured beside Kim Jong-un and was seen by some observers as the power behind the throne.

Despite his family ties to the leadership and senior status, he has been targeted by purges in the past.

In 2004, despite his place in the Kim family, he disappeared from public view.

One report at the time, citing South Korean intelligence, said Mr Chang had been placed under house arrest.

Others suggested he had been sent for "re-education". However, two years later he appeared to have been reinstated.