The lower house of the Russian parliament has given final approval to a controversial law on extremism.

The State Duma passed the bill at its third reading, with more than 270 deputies voting for the bill and 145 against.

The move comes after an upsurge in violence in major cities against foreigners and ethnic groups from southern parts of the former Soviet Union.

Racist violence has increased in recent months

But the bill has been criticised by human rights group as being too vague - they say it will allow the authorities to crack down on opposition groups which are not genuinely extremist.

It now only has to be passed by the upper house, the Federation Council, before being signed into law by Mr Putin.

Public criticism

The bill defines as extremist any attempt to forcibly change the Russian constitution, undermine the country's security, take over authority by force or carry out terrorist activities.

It also allows the police to disband parties and movements which have been identified as extremist.

Putin has given strong backing to the bill

The BBC's Nikolai Gorshkov says the government is trying to make up for public criticism that it was too slow in reacting to a recent spate of xenophobic violence in Moscow.

In a national address this week President Vladimir Putin said the law would increase the country's security.

"We will not see any extremism in Russia," he said.

'Dictatorship of the bureaucracy'

Kremlin officials say the bill is simply a legal tool to deal with racist violence.

But opposition deputies in the Duma who fought against the bill argued that it would "lead to the dictatorship of the bureaucracy".

Opponents say the bill's definition of extremism could allow police to close down religious or human rights organisations, or even the Communist Party, as well as allowing courts to hand down severe punishments for demonstrators at unsanctioned protests.

Critics argue that such laws already exist, and that rooting out intolerance in Russian society as a whole could be done more effectively by changing attitudes using education or the media.