Russian President Vladimir Putin has announced that four regions in eastern and southern Ukraine are now--according to him-- part of Russia, with 'Russian citizens forever.' This follows a Moscow-led referendum that was held in Donetsk, Luhansk, Kherson and Zaporizhzhia provinces. Kiev and its western allies call the move a 'sham', and illegal. The regions themselves make up more than 15 percent of Ukraine's territory, which president Volodymyr Zelenskyy vows to take back. But Putin has warned he'll defend those provinces - and is already looking to add more troops there. Sarah Morice begins our coverage.