Opposition activists have called off street protests in Armenia's capital Yerevan after police cracked down and a state of emergency was declared.
Riot police poured into the centre of the city on Saturday
Thousands of supporters of defeated presidential election candidate Levon Ter-Petrosian were involved in clashes with police and troops on Saturday.
They finally dispersed after a message from Mr Ter-Petrosian was read out.
Protests had continued for 11 days over alleged rigging of the vote which gave a convincing win to PM Serzh Sarkisian.
International observers judged the 19 February poll in the ex-Soviet Caucasus republic to be generally democratic.
Correspondents say the unrest has risked destabilising a key Russian ally which lies between the energy-rich Caspian Sea and the markets of Europe.
'Over the edge'
The message from Mr Ter-Petrosian, who says he is under house arrest, read: "I do not want any victims and clashes between police and innocent people."
Reports say vehicles were burnt and some shops looted
The state of emergency declared by outgoing President Robert Kocharian bans public gatherings and imposes restrictions on media reports.
It is to remain in force until 20 March.
President Kocharian told reporters that events had gone "over the edge".
"I appeal to the people of Armenia to show restraint and understanding," he said.
Official results gave Mr Sarkisian 53% of the vote, with Mr Ter-Petrosian, a former president, getting 21.5%.
The centre of the capital saw pitched battles between security forces and protesters.
Demonstrators hurled stones and petrol bombs, setting vehicles on fire, and police and troops responded with truncheons.
Reports say tracer bullets were also fired over the heads of demonstrators.
No official data on injuries and arrests among the protesters were given immediately but police say eight of their officers were injured, some seriously.
Eyewitnesses say one person was killed, possibly by a ricocheting bullet.
It "must have ricocheted as police were shooting in the air to disperse an opposition rally being held nearby", one demonstrator was quoted as saying by Reuters news agency.
A young BBC news website reader who attended the protests says she saw the body of a dead boy being taken away by ambulance.
"We saw a 12-year-old boy killed," she said.
"He was lying there, not moving. I don't know if he had been shot. That was about eleven o'clock [1900 GMT] this evening."
The same reader said she and others were chased by troops.
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