President Putin has said there will be a "harsh" response to further attacks against Russia, following an explosion on the Kerch Bridge which links his country to the annexed Crimean peninsula. As retaliation, missiles hit several Ukrainian cities, including the capital, Kyiv. NATO Secretary General Jens Stoltenberg said a deliberate attack on the critical infrastructure of Ukraine would be met with a "united and determined response". On the Sky News Daily with Niall Paterson, security and defence analyst Professor Michael Clarke explores the details behind the latest strikes and current military strength of Putin's army, and Diana Magnay, our Moscow correspondent, reports on the reaction in Russia. Also joining Niall are Dr Nick Ritchie, senior lecturer in international security at the University of York, who discusses Putin's nuclear threat, and Ukrainian MP Kira Rudik, who speaks about the resilience of her nation. Producer: Soila Apparicio Interviews Producer: Alys Bowen Podcast Promotion Producer: David Chipakupaku Editor: Paul Stanworth