The incident, which took place on Monday, was revealed after an eyewitness tweeted about it.

Mr Uwizeyimana apologised on Twitter, saying he deeply regretted what had happened.

"It should not have happened to me as a leader and public official. I already apologised to the ISCO [Intersec Security Company] staff and I now do so apologise publicly and to the public as well."

The minister later visited the security guard at her employer's office. She is pictured second-right below.

https://twitter.com/iscosecurity/status/1224694573978587136

But many Rwandans on social media continued to push for his resignation and then on Thursday, the Office of the Prime Minister announced Mr Uwizeyimana had resigned.

Their tweet also announced the resignation of Issac Munyakazi, the minister in charge of primary and secondary education:

https://twitter.com/PrimatureRwanda/status/1225529678045339648

Mr Uwizeyimana was an outspoken critic of President Paul Kagame.

When he returned to Rwanda in 2014 after some years abroad he told journalists that he had changed his views.

Two years later he was appointed to the cabinet after serving on the commission that presided over a constitutional referendum which allowed President Kagame extend his term in office.