As opposition party leader Lulzim Basha gave a speech to protesters outside the parliament in Tirana, some of those in the crowd began to hurl firecrackers, smoke bombs and flares at the government building.
Ten police officers and at least three other people were injured in the confrontation which saw the police using tear gas and water cannons to disperse a group of protesters who were advancing towards the parliament.
Prime Minister Edi Rama has faced repeated calls to stand down in recent months over claims that his centre-left Socialist Party is corrupt and has links to organised crime.
The opposition – fronted by Basha's Democratic Party – has staged protests in the capital every week since mid-February calling for Rama to stand down and for a transitional government to hold a general election.
“The whole of our battle is for a free and fair election, for European values,” said Basha.
Western powers including the EU and US have pleaded with the protesters to avoid violence and instead pursue talks with the leading party to resolve the matter.