Thousands of Greeks, including former prime minister Alexis Tsipras, marched through central Athens on Sunday evening to mark the anniversary of a violently quashed student uprising in 1973 that helped topple a military junta.

Five thousand police were deployed for the event, which often becomes a focal point for protests against government policies and regularly descends into violence. Protests this year look were dominated by opposition to the new conservative government of Kyriakos Mitsotakis, who was elected in July on a pledge to strengthen law and order. 

It is a landmark anniversary for many Greeks, with more than 10,000 people taking part in it last year. 

The demonstration marks the 46th anniversary of a student uprising at the Athens Polytechnic against the US-backed military dictatorship which was ruling Greece at the time. 

The bloodstained Greek flag that flew over the Polytechnic's iron gate, which was crushed by a tank that night, is traditionally carried at the front of the demonstration. 

At least 24 people were known to have been killed as a result of the 1973 military crackdown on the student uprising at the Athens Polytechnic. 

The protest has also been used as a channel in recent years for those involved to share their opposition to US "imperialism" and harsh austerity measures, which were imposed on Greece by international creditors following the global financial crisis. 

The Mitsotakis administration has been criticized over police operations against anarchist squats and demonstrators. There is also tension surrounding recent amendments which facilitate police checks in universities and have sparked several student demonstrations. 

Andreas Bantouvas, the Polytechnic's rector, said: "We need to be careful these days, and [public] comments must be guarded." 

Athens major Kostas Bakoyannis also expressed his urge for the city to be respected. In a message on Facebook on Friday, he said: "On this anniversary, let's send out the right message. A shared message about memory. We should not obscure the essence, which is the struggle of youth for democracy. On this anniversary, let's show respect toward the city."

Kostas Tsiaras, the country's justice minister, said to lawmakers ahead of the vote in parliament: "Laws and regulations are needed for Greek citizens to feel safe."

One example of this is harsher punishment. Throwing a Molotov cocktail (a gasoline bomb), which has been a fairly frequent occurrence at demonstrations in Greece, is now punishable by up to 10 years in prison, compared with five previously.