A year after being unceremoniously dumped as Moscow mayor, Yuri Luzhkov and his billionaire wife are back in the limelight, attacking the president and posing a problem for the Kremlin ahead of elections next month.

Over the past two weeks Mr Luzhkov and Yelena Baturina have given a barrage of interviews seemingly intended to provoke Dmitry Medvedev, the man responsible for sacking the mayor and ending his 18 years in office.

Their remarks have become increasingly aggressive. On Tuesday in an interview with the BBC, Mr Luzhkov accused the president of behaving like a “dictator” and being less democratic than Vladimir Putin.

The couple’s media blitzkrieg appears to have touched a nerve. After the former mayor’s first interview aired, Russian investigators announced they would call him in for questioning about alleged fraud at Bank of Moscow, the troubled municipal lender until recently run by Mr Luzhkov’s allies.

The Kremlin accused the former mayor of “exorbitant corruption” and inefficient city management. Last week Russia’s interior ministry said it would ask Interpol to extradite Mr Luzhkov and his wife, should they refuse to appear for questioning. The couple is currently believed to be in Austria or the UK.

Mr Luzhkov, 75, is refashioning himself as an oppositionist and claims he is being punished for insulting the president and calling United Russia officials “weak and grey”. Mr Luzhkov headed United Russia’s party list up until his dismissal.

Alexander Lebedev, a tycoon and former political opponent of Mr Luzhkov, called the mayor’s rebranding “ridiculous and complete nonsense”.

“[Mr] Luzhkov was always part of the machine and he wasn’t doing any political stuff – except as a boss in United Russia,” he said.

While Mr Luzhkov, a once popular figure in the 1990s, faces little chance of resurrecting his political career, his re-emergence poses a problem for the Kremlin, which is having trouble drumming up enthusiasm for United Russia ahead of December parliamentary elections.

Mr Medvedev appears to have lost his authority since announcing he would step down in favour of Vladimir Putin next year. Analysts said the affair has weakened the president only further, making him appear insecure and on the defence.

“[Mr] Medvedev has underestimated the public reaction,” said Stanislav Belkovsky, an independent political analyst, referring to the story’s media coverage.

“[Mr] Luzhkov does not substantiate any real problem for the Kremlin. It’s just a physiological problem and to a certain extent a political one, in that on the eve of the election [his comments] are a little painful for United Russia.”

Mr Medvedev’s press secretary denied that the Kremlin’s recent announcements about Mr Luzhkov had anything to do with the former mayor’s comments.

Mr Luzhkov is enjoying the publicity. He is suing for libel the Kremlin official who made the accusations of corruption and has promised to return to Moscow this month for questioning.

“If I did not come, I would give my opponents a trump card, give them a reason to think I am guilty in something,” he told Interfax news agency. “I will not give them that pleasure.”