More than 600 people were detained and about 100 hurt after a second night of riots in Estonia's capital Tallinn.

Police fired tear gas and rubber bullets after new clashes with mainly ethnic Russian protesters erupted over the removal of a Soviet war memorial.

Estonia says the memorial symbolized Soviet occupation. Supporters say it celebrated heroes who fought the Nazis.

Russian officials said a man who died in Thursday night's clashes was a Russian national.

A Foreign Ministry statement said the Estonian authorities had at first denied that any Russian citizens were among the casualties.

The man, who was a resident of Estonia, has been named as Dmitry Ganin.

The 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, in custody.

Russian President Vladimir Putin expressed "serious concern" about the events during a phone conversation with German Chancellor Angela Merkel, a Kremlin statement said.

Looting

The monument was removed on Friday and taken to a secret location.

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 "Rossiya, Rossiya" (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 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 BBC's Richard Galpin in Tallinn says the security forces cannot afford to take chances, with more protests expected on Saturday night.

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, our correspondent says, after what they feel has been years of discrimination against them by the majority Estonian population.

Whereabouts unknown

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 colonized 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.

Photo caption

Riot police surround the Bronze Soldier in Tallinn