A Moscow court on Friday ruled to keep four opposition activists in pre-trial jail on charges of participating in an anti-Putin rally before his inauguration last year, prolonging their arrest to one year.
The Basmanny Court heard the cases of Andrei Barabanov, Stepan Zimin, Yaroslav Belousov, and Vladimir Akimenkov, who were arrested in May and June of last year after participating in a massive opposition protest on May 6, which descended into violence and clashes with police.
The judge refused to release any of the men, who are all in their early 20s, or to change their pre-trial conditions to house arrest, according to RosUznik, the organisation that tracks trials of jailed protesters.
The rally on the eve of President Vladimir Putin's May 7 inauguration gathered an estimated 50,000 people who marched through central Moscow before trying to assemble on Bolotnaya, a square opposite the Moscow River from the Kremlin.
The rally probe, also known as the Bolotnaya probe, has already seen one protester sentenced to four and a half years in prison. Fourteen others, including the four whose stay was extended Friday, are jailed on charges of participating in the rally and using violence against police.
On Friday, investigators announced that the probe has been extended to July 6 due to the large number of witnesses and suspects, Russian agencies reported.
Earlier this week the court also extended arrests of three other suspects in the case, ignoring their complaints about health, their young children at home, and the lack of conclusive video evidence of their alleged violent behaviour at the rally.
Russia's opposition and rights campaigners argue that violence on Bolotnaya was precipitated by the actions of the police, who blocked passage to the square causing a bottleneck that panicked thousands of people.
Authorities however have painted the clashes as mass riots.
The Bolotnaya probe has also been merged with the probe into an attempt to overthrow Putin, launched after a smear film accused opposition activist Sergei Udaltsov of plotting a violent uprising against the Kremlin.
Udaltsov has been placed under house arrest while another suspect Leonid Razvozzhayev is in jail. Razvozzhayev's case caused an international outcry after he said he was kidnapped from Ukraine by masked men who tortured him before handing him over to Russian investigators.
According to watchdog Human Rights Watch, Russian civil society was subject last year to the worst repression since the fall of the Soviet Union in 1991.