* Putin signals no shift on Syria
* Says Obama is honest, but Romney could widen missile rift
* Says not meddling in Pussy Riot case
By Steve Gutterman
MOSCOW, Sept 6 (Reuters) - President Vladimir Putin signalled in an interview aired on Thursday that Russia is not ready to shift its stance on Syria, and suggested Western nations were relying on groups such as al Qaeda to help drive President Bashar al-Assad from power.
In wide-ranging remarks to Russia's RT television, Putin held out hope for an end to a dispute with Washington on missile defence if President Barack Obama is re-elected, calling him "an honest person who really wants to change much for the better".
Putin took aim at Obama's Republican rival Mitt Romney, calling his criticism of Russia "mistaken" campaign rhetoric and suggesting that a Romney presidency would widen the rift over the anti-missile shield the United States is deploying in Europe.
In some of his most extensive public comments since he started a six-year term in May, Putin dismissed Western criticism on issues ranging from Syria to the conviction of three anti-government protesters from the punk band Pussy Riot.
Putin was asked whether Moscow should rethink its stance on Syria after vetoing three Western-backed U.N. Security Council resolutions designed to pressure Assad to end violence that has killed 20,000 people.
"Why should only Russia re-evaluate its position?" he said. "Maybe our partners in the negotiation process should re-evaluate their position."
Without naming any country, he hinted the United States was looking to militants to help topple Assad and would regret it, drawing a parallel with U.S. support for the mujahideen who fought Soviet forces in Afghanistan during the Cold War.
"Today somebody is using al Qaeda fighters or people from other organisations with the same extreme views to achieve their goals in Syria," Putin said. "This is a very dangerous and shortsighted policy."
He noted that the United States had imprisoned many alleged Islamic militants at Guantanamo Bay and said it might as well "open the gates to Guantanamo and let all the Guantanamo inmates into Syria, let them fight. It's the same thing".
Putin, who has signed laws in his new term that critics call part of a campaign to suppress dissent after the biggest protests of his 12 years in power, defended such actions as necessary to instil order and said he had taken steps to improve democracy.
"What is 'tightening the screws'?" he said, according to a Kremlin transcript. "If this means the demand that everyone, including representatives of the opposition, obey the law, then yes, this demand will be consistently implemented."
Putin used a mix of moral arguments and earthy language in an exchange on Pussy Riot, three of whose members were convicted of hooliganism and jailed for two years after performing a raucous anti-Putin protest song inside a Moscow cathedral.
He prodded the interviewer to translate the first word of the band's name and made an off-colour joke about the merits of group sex but also said that "the state is obliged to protect the feelings of believers".
He denied allegations from Pussy Riot's lawyers that he had influenced the trial.