Amidst heightened tensions in Zimbabwe, President Robert Mugabe's son, Robert Mugabe Jr, has posted an archive video of his father denouncing military takeover.

In the Instagram video posted over 25 minutes ago, Mugabe is seen in an old BBC interview saying that he intends on ruling the country with 'firmness'.

"I am not going to have anybody advocating the overthrowing of government and remain in the country, he is not one of us if he does that. The alternative is to put him in detention and I don’t want to do that," Mugabe is heard saying in the video.

Robert Jr posted the video link with the caption, "Peace and love over everything".

Reports indicate that Mugabe is under heavy guard after soldiers cordoned off the parliament building and the defence headquarters as the security situation deteriorates in the southern African country, News24 reported earlier.

Robert Jr, aged 25, is currently studying towards an architecture degree at the University of Johannesburg.

He came under media spotlight when his mother, Zimbabwe first lady Grace Mugabe, caused a diplomatic storm after allegedly assaulting a South African woman who was associated with him.