Russia invades Ukraine: how it happened

Russian President Vladimir Putin has launched a full-scale invasion of Ukraine, unleashing air strikes and sending troops deep into the country, in unrest that Ukrainian authorities said left dozens dead. Weeks of intense diplomacy failed to deter Putin, who massed over 150,000 troops on Ukraine's borders in what the West said was the biggest military build-up in Europe since World War II. NATO said it had activated "defence plans" for allied countries but alliance chief Jens Stoltenberg said there were no intentions to send NATO forces into Ukraine.