Explainer: What to know as Russia invades Ukraine

A Ukrainian soldier stands next to a military vehicle on a road in Kramatosrk, eastern Ukraine (Vadim Ghirda/AP)

Russian troops have launched a broad assault on Ukraine from three sides in an attack that brought explosions before dawn to the country’s capital Kyiv and other cities.

Ukraine’s leadership said at least 40 people had been killed so far in what it called a “full-scale war” targeting the country from the east, north and south.