Greek police have raided a central university building in Athens that had been occupied by anarchist protesters for 19 days, arresting all 14 people inside and restoring the premises to academic authorities.

A police statement says four other suspected participants in the protest were arrested outside the landmark Athens University headquarters before the raid early Friday.

Anarchists invaded the building last month, draping the facade with banners and playing loud music in solidarity with jailed anarchist militants seeking better detention conditions. Greece's new radical left-led government has tabled legislation that meets many of their demands and is expected to be approved in Parliament later Friday.

Late Thursday, anarchists clashed with riot police outside the building and in surrounding areas, and another four people were arrested on suspicion of attacking officers.