Thousands of opposition supporters clashed with police outside the Albanian parliament on Saturday during an anti-government protest demanding the resignation of Prime Minister Edi Rama.
Critics have accused the socialist prime minister, in power since 2013, of corruption.
Police fired tear gas and water cannons at protesters, some of whom tried to enter the parliamentary building in Tirana by forcing their way through the main entrance.
Five police officers and about 10 demonstrators and journalists required hospital treatment, mostly for breathing problems after the clashes, the health ministry said.
Protesters repeatedly tried to break through police lines.
Several windows were broken as some demonstrators threw smoke grenades and stones toward the parliament building.
"The situation is out of control," said Lulzim Basha, an organizer of the protest and leader of the main opposition center-right Democratic Party.
He blamed the police for having let the demonstrators get too close to the building so as to "incite violence" and allow Rama to denounce the opposition.
On Wednesday, Basha told a meeting of his supporters that "the 16th of February will be the last day in power for Rama."
Saturday's demonstration in the capital was the latest in a series that Basha has organized.
An opposition coalition of five parties, ranging from the center-right to the center-left, has accused Rama of "collusion with organized crime" and plunging "the country into corruption and poverty."
They want him to stand aside in favor of a government of technocrats who would prepare early parliamentary elections.