Ukraine crisis: Heavy bombardment in rebel-held Donetsk

There has been intense artillery bombardment overnight in the eastern Ukrainian city of Donetsk.

The fighting comes a day after monitors saw large numbers of unmarked military vehicles in rebel-held areas. Ukraine says it believes the rebels have received equipment from Russia.

Moscow denies this, although in the past it has said that Russian soldiers on leave were fighting among the rebels.

David Stern reports from Kiev.