MOSCOW (Reuters) - Russian investigators increased pressure on one of President Vladimir Putin's biggest critics on Thursday, opening a new criminal investigation against Alexei Navalny a day after he went on trial on theft charges.
Navalny, who has helped organise a wave of protests against Putin and is a campaigner against state corruption, denies any wrongdoing and says charges are being falsified against him as part of a Kremlin campaign to crush the opposition.
Russia's Investigative Committee, which answers directly to Putin, said Navalny and his brother Oleg were suspected of defrauding a company out of 3.8 million roubles ($120,000) by organising mail transport for them at excessive prices in 2008.
It is the fourth criminal case opened against Navalny in recent months.
Navalny reacted wryly to the announcement of the new investigation on his Twitter feed as he travelled back to Moscow by train after going on trial on Wednesday on charges of theft in the city of Kirov.
"I woke up on the train. I found out that another criminal case has been launched. That means our trip was successful," he wrote.
The 36-year-old faces up to 10 years in jail in the trial that opened on Wednesday if he is convicted of stealing about $510,000 from a timber firm he was advising in Kirov in 2009. The trial has been adjourned until April 24.
The most prominent opposition leader to be tried in post-Soviet Russia, Navalny says he believes Putin, 60, ordered the investigations and trial against him to sideline him as a potential presidential rival.
The Kremlin denies putting pressure on the courts and says Putin does not use them for political ends. But Putin's former Finance Minister Alexei Kudrin cast doubt on the trial this week, saying it may harm Russia's investment image.
Navalny has been a thorn the government's side since starting an online campaign against state corruption in 2007.
A ruling party deputy was forced to resign in February when Navalny revealed on his blog that he had failed to declare $2 million worth of property in the U.S. state of Florida.
"It is obvious that all the cases against Navalny are politically motivated," veteran Russian rights activist, Svetlana Gannushkina, told Interfax.
Since Putin's return to the Kremlin last May after four years as prime minister, two members of the dissident punk band Pussy Riot have been jailed, a prominent protest leader has been thrown out of parliament and another is under house arrest.
In addition to the case that has put Navalny in the dock, he has been charged with embezzling up to $3.24 million from a political party in 2007.
Investigators said the latest case will be bundled together with another ongoing investigation into suspicions that Navalny, along with his brother, cheated a mail-transport company out of $1.79 million.
A spokesman for the Investigative Committee said last week that cases against Navalny had been speeded up because he had taunted the authorities.
More than a dozen protesters also face sentences of up to 10 years over clashes with police at a rally on the eve of Putin's inauguration last May, after which parliament pushed through stiff new penalties for demonstrators who stray out of line.
A group of human rights and opposition activists blamed riot police for initiating the clashes at the May 6 rally across the river from the Kremlin in a report published on Thursday.
The report, based on 600 witness interviews, case and video materials, accuses the authorities of exaggerating the scale of the violence and using excessive force.
About 600 protesters were detained at the rally, part of a campaign of protest against Putin's 13-year dominance of politics that at its peak saw 100,000 Russians on the streets but has since lost steam.
(Reporting by Alissa de Carbonnel; Editing by Pravin Char)