SEOUL (AFP) - North Korea's ambassador to Malaysia, a relative of leader Kim Jong Un, has been recalled just days after the young supremo's uncle was apparently ousted in a leadership purge, according to a report.

The South's National Intelligence Service (NIS) told a parliamentary committee on Tuesday that it believed Mr Kim's uncle and political regent Jang Song Thaek had been removed and two associates executed.

Now Mr Jang's nephew Jang Yong Chol, the North Korean ambassador to Malaysia, is believed to have been called back to Pyongyang, an intelligence source in Bejing told Yonhap news agency.

The ambassador's wife and two sons were spotted on Thursday before boarding an Air Koryo flight to Pyongyang in China's north-eastern city of Shenyang, Yonhap said, citing multiple witnesses.

It said the ambassador was believed to have been recalled earlier.

Mr Jang Song Thaek's apparent dismissal is particularly noteworthy given the crucial role he was seen as having played in securing Mr Kim's own succession after his father Kim Jong Il's death.

The NIS assessment triggered a wave of conjecture as to why Mr Kim had turned on the 67-year-old who helped put him on the throne, and what it said about the young leader's grip on power.

However, the NIS report was only an assessment, and the main question regarding Mr Jang's dismissal is still whether it actually happened or not.