A tense calm is reported in Estonia's capital, Tallinn, after two nights of clashes between ethnic Russians and police over a Soviet war monument.
One man was killed, 153 people were injured and some 800 arrests were made as the Russians resisted the removal of the bronze statue of a soldier.
Police fired tear gas and rubber bullets and protesters trashed shops.
Estonians say the memorial symbolised Soviet occupation. Supporters say it celebrated heroes who fought the Nazis.
The dead man has been named by the Russian embassy in Tallinn as Dmitriy Ganin, 20, an ethnic Russian who was permanently resident in Estonia and held Russian citizenship.
Estonian authorities have said he was stabbed by another demonstrator and that police had no involvement in his death.
There have been unconfirmed reports of a second death, but the Estonian government has denied this.
Russian President Vladimir Putin expressed "serious concern" about the events during a phone conversation with German Chancellor Angela Merkel, a Kremlin statement said.
The monument was removed on Friday and taken to a secret location.
1918: Estonia gained independence from Russia
1940: Forcibly incorporated into Soviet Union
1941-1944: Occupied by Nazi Germany
1944: Soviets return as Nazis retreat
1991: Gains independence as Soviet Union collapses
1994: Last Russian forces leave Estonia
Now: Ethnic Russians make up quarter of Estonia's 1.3m people
Correspondents said a crowd of more than 1,000 demonstrators gathered on Friday evening where the monument used to stand.
Some of the protesters threw petrol bombs, while others waved Russian flags and chanted "Russia, Russia, Russia".
Department stores and other shops in the city centre were looted.
There were also reports of rioting and looting in the towns of Johvi and Kohtla-Jarve, in a mainly ethnic Russian region east of Tallinn.
AFP news agency said that in Johvi looters set fire to a statue of an Estonian general who fought the Russians during the country's 1918 war of independence.
By Saturday morning the situation in central Tallinn was described as calm, but the authorities are braced for more trouble.
Squads of police were seen moving around the area where the memorial used to stand.
The decision to remove the Soviet monument has strained relations with Russia, which called it "blasphemous".
And for local ethnic Russians it is one insult too many, the BBC's Richard Galpin says, after what they feel has been years of discrimination against them by the majority Estonian population.
More than a quarter of Estonia's 1.3m people are ethnically Russian, and speak the language.
However, half of them do not have Estonian citizenship.
But the Estonians believe much of the tension is being whipped up by forces outside the country, i.e. Russia itself.
During the years of Soviet occupation after World War II, tens of thousands of Estonians were killed. And they say their country was effectively colonised with many Russians being brought in as workers and military personnel.
Estonia's government would not reveal where it took the six-foot (1.83m) statue, but spokesman Martin Jasko said it would ultimately be placed at the military cemetery in Tallinn.
The memorial, a bronze statue of a Soviet soldier, was erected in 1947. The remains of Soviet soldiers are thought to be buried nearby.