A St Petersburg politician who authored the Russian city’s anti-gay law is taking legal action against Lady Gaga for speaking out for LGBT rights during her show.

Vitaly Milonov, the United Russia party deputy who created the controversial St Petersburg act that prohibits ‘the promotion of homosexuality to minors’, claims the pop superstar broke the law at the beginning of her concert in the city at the weekend.

‘We will contact prosecutors and the law enforcement agencies to carry out a thorough investigation of the situation,’ Milonov told Russian newspaper Life News.

‘When people tell kids "you must support sexual minorities", that can create a false equivalence for them between traditional and non-traditional relationships.’

The Born This Way singer told fans at the opening of her gig that she ‘expects respect’ for gay rights and wants to unite everyone.

It followed a tweet on Saturday (8 December) in which she expressed her ‘gratitude’ to Prime Minister Dmitry Medvedev for opposing anti-gay regional laws in Russia.

If sued, Lady Gaga wouldn’t be the first foreign artist to fall foul of the city’s draconian law, after anti-gay activists filed a $10 million lawsuit against Madonna.

During the MDNA gig in August, the Material Girl told fans to ‘show your love and appreciation to the gay community’, had pink wristbands distributed to the audience and dressed in black lingerie with the words ‘No Fear’ scrawled on her bare back.

St Petersburg and the Russian states of Arkhangelsk, Ryazan and Kostroma have already adopted anti-gay laws.

A similar bill is due to be debated in the State Duma and if passed would ban ‘homosexual propaganda’ across the country.

The laws have been roundly condemned by Europe, the US State Department, human rights organizations and lesbian, gay, bisexual and transgender campaigners and individuals as well as their straight allies.