Students in the Bulgarian capital Sofia have chained the doors of the country's biggest university as anti-government unrest continues.
After occupying a lecture hall for nearly three weeks, they declared "total and effective occupation" to demand the government's resignation.
Thousands joined a student march through the city on Sunday.
Unrest over poverty and corruption in the EU's poorest state has continued despite early elections in May.
A Socialist-backed technocratic government was formed under a new Prime Minister, Plamen Oresharski, but has lost support amid allegations of corrupt ties with business groups.
Similar popular unrest had plagued its predecessor in power, a centre-right minority government led by Boyko Borisov.
'Time is up'
Academic business at the university was "brought to a complete halt" as protesters were not allowing either teachers or administrative staff to enter the university, according to the Novinite news agency.
Sit-ins, the agency added. were under way at 15 universities across the country. "We are protesting against poverty and unemployment", a student declaration said, quoted by AFP news agency. "We are protesting before we become beggars with a higher education."
On Sunday, university professors and teachers issued a statement condemning the "lies and 'tycoonisation' of the political and social environment".
One banner, seen by Reuters news agency, read "Your time is up! 24 years of false transition is enough", referring to administrations since the end of communist rule in 1989. Other banners read "Down with the mafia" and "We stay, you emigrate".
President Rosen Plevneliev, who is from Mr Borisov's GERB party, told a French magazine he supported citizens calling for a "moral revolution"
Asked by Le Nouvel Observateur about the allegation that the current government was backed by a "Red Mafia", he added: "The mafia does not have a definite colour. What is certain is that what we call 'mafia' is a pathology of our democracy that we must eradicate."
The desperation of many Bulgarians has been brought home by a series of self-immolations since the start of the year. At least nine people have burnt themselves to death, according to Novinite's figures.