In an extraordinary incident, American journalist, author and editor at The Intercept, Glenn Greenwald was subjected to a physical attack from Brazilian reporter Augusto Nunes, who was interviewing him on the “Jovem Pan News” radio station, on the show “Panico”.

The video (above) shows the two men in a heated argument in Portuguese, with the disagreement escalating when Nunes slaps Greenwald. The brawl is quickly broken up by a third person who enters the frame to mediate.

According to an online report by The Rio Times, the incident was instigated by Greenwald’s calling Nunes a coward for commenting on him and his husband’s children. After the assault, the moderator of the show interrupted the programme for 12 minutes.

An extended clip (below) shows the brawl continuing, with four to five people intervening to help diffuse the situation.

Recently, Greenwald has become something of a focal point in Brazilian politics. He has faced backlash from the far right after publishing a series of articles highlighting the illegitimacy of Brazil’s largest ever anti-corruption investigation.

His reporting has been especially damaging to the Jair Bolsonaro government, following a trove of leaked mobile phone messages, reported The Guardian.

Glenn Greenwald is best known for a series of reports he wrote in 2013 for The Guardian, detailing the United States’ and Britain’s global surveillance programmes. The reports came from classified documents disclosed by Edward Snowden, American whistleblower and ex-CIA employee, who contacted Greenwald with the files.