US Senator John McCain on Thursday accused Russian President Vladimir Putin of allying himself with tyrants and ruling through violence and repression, in a scathing retort to a New York Times editorial by Putin earlier this month.In an editorial published on news website Pravda.ru, McCain criticized the Russian leader's policies at home and in Syria, where Putin has repeatedly protected President Bashar Assad."(Putin) is not enhancing Russia's global reputation. He is destroying it. He has made her a friend to tyrants and an enemy to the oppressed, and untrusted by nations that seek to build a safer, more peaceful and prosperous world," wrote the senior senator from Arizona, who is also a leading Republican voice on military affairs. Pravda.ru considers itself a successor to the Soviet-era Communist Party newspaper but is not connected to it. Like the newspaper, which still exists, it has a limited readership.US-Russia ties are at one of their lowest points since the Cold War as tensions over human rights and the fate of fugitive ex-U.S. intelligence contractor Edward Snowden, to whom Russia awarded asylum, have added to tensions over the Syrian conflict.Putin's op-ed article took issue with US President Barack Obama's claims of "American exceptionalism" and said a military strike against Assad could escalate the conflict that has already killed more than 100,000 people.Russia has blocked three consecutive UN resolutions aimed at pressuring Assad to end violence and has held talks on a plan enabling the Syrian leader to give up his chemical weapons to avoid possible U.S. military strikes.McCain, who is known in Russia as one of the Kremlin's harshest critics, warned Putin in 2011 that "the Arab Spring is coming to a neighborhood near you" when fraud allegations triggered mass street protests after a parliamentary election. The senator has been critical of Putin's domestic policies, including Moscow's response to the protest movement that has all but died out after Russia's parliament passed laws that critics say are intended to clamp down on dissent."President Putin and his associates ... don't respect your dignity or accept your authority over them. They punish dissent and imprison opponents. They rig your elections. They control your media," McCain wrote.After Russia gave asylum to Snowden, who is wanted by U.S. authorities, McCain said Washington should complete missile-defense programs in Europe and expand NATO to include Russian neighbor Georgia - both endeavors that are anathema to Moscow.McCain also made reference to dead whistleblower Sergei Magnitsky, who died in pre-trial detention after accusing officials of a $230-million fraud, and mentioned recently passed laws criticized in the West for being anti-gay.He also said that the members of the protest punk band Pussy Riot, two of whom are serving time behind bars for a protest against Putin in a Moscow cathedral, had been convicted on political grounds."They write laws to codify bigotry against people whose sexual orientation they condemn. They throw the members of a punk rock band in jail for the crime of being provocative and vulgar and for having the audacity to protest President Putin's rule," he said.