The Ukrainian army is using artillery today on a notorious rebel spot as can be seen in a video from Graham Phillips (a biased Russia Today journalist, but with great videos on location): https://www.youtube.com/watch?v=4mvysWGw2EY
The line of sight in this video is from top right to bottom left in the picture below. The shells come from near the tv tower in the left bottom corner and arrive at the train positioned across the road as a blockade.
#BreakingFootage First visual evidence,the Ukrainian army is indeed using artillery vs.rebels in #Sloviansk. #Ukraine pic.twitter.com/6PLxqcMbg0
— ConflictReporter (@MiddleEast_BRK) 17 mei 2014
And the result is this:
#Sloviansk militia position at railway line pretty much destroyed by the UA army shelling. more pics at @SergeyGall pic.twitter.com/gkrJlfy5Di — Crimea&East (@IndependentKrym) 17 mei 2014