Brussels, March 27 (IANS): The European Union's diplomatic service on Monday demanded the release of demonstrators who were arrested during an anti-corruption protest in Russia.

In a statement, the European External Action Service (EEAS) said the detained citizens, including opposition leader Alexei Navalny, who were arrested during a series of anti-corruption protests, should be released as they had the right to gather peacefully and to free speech, Efe news reported.

"Police operations in the Russian Federation prevented the exercise of basic freedoms of expression, association and peaceful assembly - which are fundamental rights enshrined in the Russian constitution," read the statement.

The EEAS called on Russian authorities to respect the international commitments it had made to the European Council and the Organisation for Security and Co-operation in Europe.

Meanwhile, the head of the Council of Europe on Monday also urged Russian authorities to release the opposition protesters who were arrested in the mass demonstrations in cities such as Moscow and St. Petersburg.

Secretary-General Thorbjorn Jagland said in a statement that those detained during the protests were exercising their freedom of expression and peaceful assembly.

The arrests "raise issues under the European Convention on Human Rights," Jagland said.

"I am particularly concerned about the reported detention of minors. I call for the release of all those detained," he added.

On Sunday, thousands of people gathered across Russia to protest against corruption in the country in a series of rallies called up by Navalny.

As the demonstrations were unauthorized, hundreds of people were arrested, including the opposition leader, who once detained tweeted: "Guys, I'm fine. Our focus of the day is the fight against corruption," urging his followers to ignore his arrest and continue protesting.

Navalny is to face a hearing on Monday, and on Twitter posted a picture of himself in court with the caption: "The time will come when we judge them (but honestly)".

The national protest day was organised by Navalny under the slogan "Dimon (a derogatory diminutive of Dmitry) will pay," referring to Prime Minister Dmitry Medvedev, whom the opposition leader accuses of being the most corrupt man in Russia.

The accusation was first made in early March, when Navalny published a video on YouTube that showed the results of a months-long investigation into the Prime Minister.

The video, which has been seen more than 10 million times, claimed Medvedev had illegally received at least $1.2 billion worth of property and funds through charitable foundations run by close friends and family.

Earlier this year, Navalny was found guilty of corruption in a case he said was fabricated for political motives, meaning he would no longer be able to run in national elections.