Amid a one-day transport strike in Greece, a few thousand students and teachers joined the protest against austerity measures by marching through Athens.
They are opposed to education reforms that will see some institutions merged.
The strikes and demonstrations come a day after the government announced another round of spending cuts.
Prime Minister George Papandreou is on a drive to win over not just opponents but his own party. His message as he welcomed MPs from the Greek islands: there is no alternative.
“No other road exists, any other road would mean bankruptcy and serious consequences for every household, for every Greek. So that’s why we’re making this big effort and it would be very negative to abandon it: the sacrifices we’ve already made would be lost,” he said.
Transport was severely disrupted as workers went on strike against the belt-tightening plan designed to save Greece from bankruptcy.
Taxi and bus drivers, metro and rail workers stayed away, provoking traffic jams as commuters took to their own cars.
Dozens of flights were cancelled or delayed after air traffic controllers stopped work.