Members of pro-communist union PAME gather during a protest in Athens (AP)

Protester kicks back a tear gas canister at riot police (AP)

Protesters gather during a demonstration in Athens (AP)

Anti-austerity protesters march through Athens' central Syntagma square (Reuters)

Riot police run by closed shops after protesters threw a petrol bomb (Reuters)

Masked protesters throw rocks at policemen following an anti-austerity march (Reuters)

Demonstrators march during an anti-austerity rally in central Athens (Reuters)

A man cycles past a closed bank in central Athens (Reuters)

Protesters with placards reading 'Merit' and 'Firing' (AP)

Riot police stand behind smoke from tear gas (AP)