Ukraine: Explosions and gunfire heard after Russia launches invasion

Russian forces have launched a military assault on neighbouring Ukraine, crossing its borders and bombing military targets near big cities.

A residential building in Chuguev was destroyed after it was shelled.

Russian President Vladimir Putin has warned that Moscow's response will be "instant" if anyone tries to take on Russia.

Ukraine has urged the UN "to do everything possible" to stop what it says is a full-scale war.