Russia and the European Union clashed over President Putin's human rights record today as their summit ended without agreement on ways to improve the increasingly strained relationship.

The former chess champion Garry Kasparov was among opposition leaders barred by police from flying to a protest march in Samara, close to the site of the summit, prompting criticism from Germany's Chancellor Angela Merkel at a news conference with Mr Putin.

"I'm concerned about some people having problems in traveling here. I hope they will be given an opportunity to express their opinion," she said.

Mr Putin dismissed the protesters who had planned to join a March of Dissent in Samara as "marginal groups", saying: "They don't bother me in any way."

He sought to deflect criticism by pointing to protesters held by police in Germany, which holds the EU's rotating presidency. Mr Putin said: "Law enforcement authorities in practically all countries make preventative arrests...Such action isn't always justified.

"But I assure you that everyone who wants to stage a demonstration in accordance with legislation and without violating the laws and regulations of the Russian Federation will receive such an opportunity."

Jose Manuel Barroso, the European Commission President, said that democratic freedoms were "sacred principles" for the EU. He said: "We stress the importance of democracy, freedom of the press, freedom of association, freedom of demonstration.

"It's very important for all European countries, and Russia is a European country ... to ensure the full respect of those principles and values."

Mr Kasparov was among 27 people, including foreign journalists, detained at Moscow's Sheremetyevo airport by police. They were held for five hours until the last available flight to Samara had left.

Speaking from the departure lounge, Mr Kasparov told The Times: "We have been detained here and can't leave. The police have taken our passports and are claiming our tickets are counterfeit.

"We tried to go out but they prevented us from doing so. We are being held without charge or explanation and they did not allow us to contact lawyers."

As Mr Kasparov and Eduard Limonov, another opposition leader, were being detained, members of the Kremlin-backed Nashi youth group, dressed in white medical gowns, handed out leaflets warning that the pair were mentally unstable and a danger to other passengers.

Mr Kasparov is one of the leaders of The Other Russia, an umbrella organisation of groups that accuse Mr Putin of crushing democratic freedoms and of creating a police state governed by former KGB agents.

The march in Samara was part of The Other Russia's campaign of street protests aimed at stirring support for an anti-Putin candidate in next year's presidential elections. The Kremlin has cracked down hard on previous demonstrations, but the Samara protest had been sanctioned to avoid EU criticism at the summit.

Mr Putin's spokesman Dmitry Peskov rejected claims that the Kremlin had ordered Mr Kasparov's detention. He said: "The Kremlin was not in Sheremetyevo. I don't think the issue of the non-arrival of a Russian citizen, even a famous one... will be on the summit agenda."

Mr Putin and Ms Merkel sought to make the best of a summit at which not a single agreement was signed, but the chill in relations was evident.

"Our talks today showed that we're not co-operating very intensively, but also beginning co-operation in new areas," Ms Merkel admitted.

"We need each other, we are open for an honest dialogue between Russia and the EU," Mr Putin said. "But we must defend our interests in the same professional way as our partners do."

Talks on a new co-operation agreement remain stalled by a dispute over a Russian ban on meat imports from Poland. Russia's clash with Estonia over a Second World War monument have further soured relations, and there are disagreements with Lithuania over oil deliveries.

Mr Barosso made clear that all three states enjoyed full EU support. He said: "We had occasion to say to our Russian partners that a difficulty for a member state is a difficulty for the whole European community."

Mr Putin retorted that "economic selfishness" by some members was threatening the interests of the EU as a whole. He said: "I asked my colleagues, and they did not take offence: are there any limits to this solidarity?"

Between 200 and 300 demonstrators eventually staged a protest against Mr Putin in Samara, watched by a heavy police presence. Organisers had complained of a campaign of harassment by the authorities in the run-up to the march.

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