A senior Russian official has implied that Madonna is a moralising "slut" after the singer used a Moscow concert to state her support for the jailed feminist punk band Pussy Riot.

"With age, every former s. tries to lecture everyone on morality," Dmitry Rogozin, a deputy prime minister, wrote on Twitter late on Wednesday, using the first letter of the Russian word for "slut" or "whore". "Especially during overseas tours."

Madonna scrawled "Pussy Riot" across her back and performed "Like a Virgin" wearing the band's trademark balaclava during a concert in Moscow on Tuesday. She praised the band's three women – Nadezhda Tolokonnikova, Maria Alyokhina and Yekaterina Samutsevich – for being courageous and said she was praying for their freedom.

The women are facing a three-year prison sentence on charges of hooliganism motivated by religious hatred after performing an anti-Putin "punk prayer" in a Moscow cathedral. A verdict is due on 17 August.

Madonna is the highest-profile star to come out in support of the group. Artist Yoko Ono issued a statement calling for their freedom earlier this week.

The tens of thousands of fans inside Olimpisky Stadium greeted Madonna's gesture with wild applause. One Twitter user challenged Rogozin's statement on Madonna, tweeting: "She spoke about freedom, it's government officials that lecture us every day on all the state channels".

Rogozin, a former ambassador to Nato, replied: "Either take off the cross or put on [under]pants."

Madonna is due to perform in St Petersburg on Thursday evening and has promised to issue a message against the city's new draconian law banning "homosexual propaganda".

The Russian Orthodox church has decried Madonna's appearance in Russia, with one priest urging believers to call in bomb threats to the St Petersburg venue in order to disrupt the show.

The US embassy in Moscow has issued a statement warning citizens of the potential for violence.