* Court sentences two protest leaders to 4.5 years jail each
* Putin accused of clamping down on opponents
* President denies tightening screws on foes (Adds sentencing)
By Maria Tsvetkova
MOSCOW, July 24 (Reuters) - A Russian court sentenced two protest leaders to 4.5 years each in jail on Thursday on charges of inciting mass riots against President Vladimir Putin, in a case the opposition sees as part of a clampdown on his foes while all eyes are on Ukraine.
Sergei Udaltsov, who shouted 'Freedom!" as he was led from the court room, and Leonid Razvozhayev were both accused of coordinating protests which turned violent on May 6, 2012, the eve of Putin's inauguration for a third term as president.
The state prosecution had called for eight-year jail terms.
"Udaltsov, Razvozhayev ... agreed between themselves repeatedly on the organisation of mass disorders on the territory of the Russian Federation," Judge Alexander Zamashnyuk told the Moscow court.
During a more than nine-hour reading of the verdict, the judge was repeatedly interrupted by shouts and applause in support of the defendants, who listened in grim silence.
The two denied the charges of organising mass riots and plotting wider unrest, portraying themselves as victims of a political witch-hunt and a crackdown on civil liberties.
"It's a disgrace to our country to hand such sentences to innocent people," Udaltsov's wife Anastasia said after the verdict. "They don't have a single shred of proof of his guilt."
Udaltsov, 37, a fiery orator with a shaven head who dressed in black for the hearing, was one of the most prominent leaders of the opposition movement that organised urban protests against Putin in the winter of 2011-12 that have long since faded.
He has been under house arrest since February 2013.
Razvozhayev, 41, an aide to a member of parliament who is critical of Putin, says he was abducted in Ukraine, smuggled into Russia and forced into signing a confession, which he later disavowed. He was also sentenced to pay a fine of 150,000 rubles ($4,300) on Thursday.
The two men's lawyers said they would appeal the sentence both in Russia and at the European Court of Human Rights.
The prosecutors' case was built in part on a documentary broadcast by the pro-Kremlin TV channel NTV, which alleged the two activists were paid to plot unrest by a politician from neighbouring Georgia, with which Russia fought a war in 2008.
Police detained more than 400 people and dozens of officers were hurt in clashes in May 2012 after authorities restricted the rally on Bolotnaya Square across the river from the Kremlin.
"Seventy-eight representatives of the authorities (police) were injured," the judge told a hearing attended by many opposition activists, two of whom were ejected for being "too emotional".
"The Court recognises as indisputably proven that on May 6 2012, the demonstration ... escalated into mass riots that led to violence and the destruction of property," he said.
Kremlin critics accuse police of starting the violence at the Bolotnaya rally to discredit the opposition as Putin returned to the presidency after four years as prime minister.
They say the Kremlin uses pliant courts for political purposes and highlight the jailing of seven people in February over the rally.
"The verdict in the Udaltsov-Razvozhayev trial is just a rewrite of the prosecutors' case," said a post on the Twitter feed of another prominent protest leader, Alexei Navalny, who is under house arrest after receiving a suspended five-year sentence on charges of theft.
Putin denies political interference in court cases but says anyone who attacks the police should be punished.
In his third spell as president, following two successive terms from 2000 until 2008, Putin has adopted an increasingly conservative stance to consolidate his public support.
His popularity has risen to new heights in Russia since the annexation of the Black Sea peninsula of Crimea from Ukraine in March. However, he could become an international pariah if Russia is found to have provided missiles to rebels in eastern Ukraine, where a Malaysian passenger jet was brought down last week, killing 298 people.
Putin said this week he would not tighten the screws on his opponents.
However, his critics say Putin has quietly enacted laws aimed at curbing dissent, including legislation envisaging tougher punishment for people involved in riots and imposing life sentences for various "terrorist" crimes.
He has also approved tighter controls on bloggers, some of whom have emerged as opposition leaders and have used the Internet to criticise Putin and to arrange protests. (Reporting Maria Tsvetkova,; Writing by Timothy Heritage and Alissa de Carbonnel; Editing by Gareth Jones)