Moscow, March 19 : Russian President Vladimir Putin has paid a surprise visit to Mariupol -- the Ukrainian port city captured by Russian forces, the media reported. The visit is believed to be Putin's first to a newly-occupied Ukrainian territory. In a video, Putin is seen driving a car through streets at night and speaking to people, the BBC reported on Sunday. It was, however, not known when the footage was taken. During the visit, the Russian President is also reported to have met top military commanders in Rostov-on-Don city. Putin travelled to Mariupol by helicopter. In the video, he is in the car with Russia's Deputy Prime Minister Marat Khusnullin, who explains how the city is being rebuilt, Tass news agency reported. Putin also appears to visit the Philharmonic Hall, which was used to stage trials of defenders of the Azovstal iron and steel plant, a huge industrial complex where Ukrainian troops held out before eventually surrendering. Mariupol has been under Russian occupation for more than 10 months after being devastated in one of the longest and bloodiest battles of the conflict. Ukraine said more than 20,000 people were killed there. UN analysis estimates that 90 per cent of the buildings were damaged and around 3,50,000 people were forced to leave, our of a pre-war population of about 5,00,000. A group of local residents has told the BBC that "Russia is conducting an expensive campaign to rebuild the city and win over the hearts and minds of its people". The purpose is to assimilate Mariupol and make it Russia's own. Russian authorities say 3,00,000 people are now living there. /IANS