Three men were shot dead as protesters battled police at an anti-government rally in the Albanian capital on Friday, in what Prime Minister Sali Berisha called an opposition attempt to foment a Tunisia-style uprising.
Supporters of the opposition Socialist Party, which refuses to accept the result of a 2009 election, protested outside Berisha's office against what they see as official corruption and electoral fraud.
Some pelted the building and police with stones, sticks and umbrellas. Police responded with tear gas, rubber bullets, water cannon and stun grenades. Smoke billowed from burning cars, some of them police vehicles.
"The bastard children of Albania's own Ben Alis conceived Tunisian scenarios ... for you citizens of Albania," Berisha said, comparing his Socialist foes with ousted Tunisian President Zine El-Abedine Ben Ali.
Socialist Party leader Edi Rama said the crowd was provoked and police had behaved unprofessionally.
The violence was the worst since the European Union applicant country spun out of control after the storming of the government building after the death of a lawmaker in 1998.
"Albania is not in a state of emergency and will not pass into a state of emergency. But scenarios of violence will not be tolerated," Berisha said.
Alfred Gega, deputy director of Tirana's Military Hospital, told reporters three civilians had died, one with a gunshot wound to the head and the other two with bullet wounds to the chest from close range.
Some 33 protesters and 17 policemen were wounded. A civilian and a policeman were in critical condition, Gega added.
Protesters packed the main boulevard. Witnesses estimated the crowd size at around 20,000; the opposition reported there were more than 10 times as many.
"I call for calm and maturity," President Bamir Topi said after the violence erupted. "Albania needs to heal its wounds, not to open new ones."
After about three hours of clashes police in riot gear dispersed the crowd and took control of the boulevard. Live television pictures showed police chasing stray lone protesters and beating them with truncheons.
The opposition Socialists called for new elections after refusing to accept the results of the June 2009 parliamentary polls, which Berisha's Democratic Party won by a wafer-thin margin. Talks to break the deadlock have repeatedly failed.
Berisha's ally Ilir Meta, head of his junior coalition partner, resigned as deputy prime minister a week ago after being accused of corruption. Tension had escalated this week after sharp exchanges of accusations in parliament.
"My call for the so-called premier is to refrain from taking our society and country further down a blind alley," Rama said. Protesters would observe mourning on Saturday for the dead, and later hold more protests, which would be peaceful, he said.
In a joint statement, the Tirana missions of the EU, United States and Organisation for Security and Cooperation in Europe deeply regretted the casualties and called for a compromise.
"Violence and excessive use of force cannot be justified and should be avoided. We urgently appeal for calm and restraint on all sides and to abstain from provocations," they said.
The European Union rejected Albania's application last year for the status of official candidate to join the bloc, urging it to fight corruption and establish a functioning democracy.