A group of Greek anarchists disrupted the evening news broadcast of state ERT TV on Tuesday after forcing their way past a guard to enter the live studio.
Anchorman Panos Haritos said the anarchists wanted to read a protest text on air. During the negotiations, producers switched to archive footage.
Haritos said he offered to read the text instead but the protesters refused and left.
The text wasn't revealed and it wasn't clear what the protest was about.
An interviewee on the program said the anarchists injured a cameraman and police later detained 24 protesters.
The group has also staged high-profile protests in the grounds of Greece's Parliament and at the offices of political parties, and has smashed the offices of the country's privatization agency.