Several Ukrainian checkpoints attacked across all Donetsk area?

Many reports have been going out of attacks on several different checkpoints today. Yet, this concerns the same ambush on an Ukrainian convoy, but refers to different villages nearby.

The deadliest day in East Ukraine conflict as dozens of Ukrainian soldiers killed following multiply attacks on local checkpoints
— Maxim Eristavi (@MaximEristavi) 22 mei 2014

#Olhinka+#Soledar - 33 dead via @Renat_Kuzmin election HQ #Volnovaha - 8 dead via Defense Min #Blahodatne - 11 dead via @AP
— Maxim Eristavi (@MaximEristavi) 22 mei 2014

Olginka

Outside village of Olginka, south of Donetsk. Checkpoint attacked early today. Soldiers not letting us close.
— Kevin Bishop (@bishopk) 22 mei 2014

Blahodatne 

AP count 11 killed in rebel ambush on Ukrainian checkpoint at a place called Blahodatne. http://t.co/vKQtcvI5CW
— Roland Oliphant (@RolandOliphant) 22 mei 2014

BLAHODATNE, Ukraine (AP) — AP journalists have seen 11 dead bodies at a Ukrainian military checkpoint http://t.co/6GlBqMHh60
— Olaf Koens (@obk) 22 mei 2014

Volnohava

Footage of destroyed BMPs near #Volnovakha in #Donetsk oblast https://t.co/58XxfBr39Q
— /r/UkrainianConflict (@UkraineConflict) 22 mei 2014

Some of them are dead now. Men of #Volnovaha CP. #ATO #Ukraine pic.twitter.com/XSNN6Q5sKI
— lennutrajektoor (@lennutrajektoor) 22 mei 2014

This is response from 2 helicopters on the attackers:

Picture of #Volnovaha massacre. Speechless. Band of idiots not army generals or #ATO GS. pic.twitter.com/TbfLGiCQGh #Ukraine
— lennutrajektoor (@lennutrajektoor) 22 mei 2014

Also ambulances were attacked!!!

#Terrorists at E. #Ukraine shot at medical car @Dbnmjr pic.twitter.com/gY4tib49d9 | EMPR
— Euromaidan PR (@EuromaidanPR) 22 mei 2014

from t ground RT “@bishopk: Soldier in hospital at Volnovakha tells us 15 dead, 31 injured in attack on Ukrainian checkpoint this morning.”
— Natalia Melnychuk (@pravolivo) 22 mei 2014

@djp3tros Yes! The convoy of 51th mechanised brigade was destroyed between Olginka & Blahodatne. Not at the checkpoint, not National Guards.
— Лiсовий брат (@forest_brother) 22 mei 2014

About the attackers:

#Ukraine officer at #Volnovakha hospital tells @KyivPost that up to 20 attackers were involved, and "I'm sure they were mercenaries."
— Christopher Miller (@ChristopherJM) 22 mei 2014

Aftermath of the attack:




Also read about another ambush on an Ukrainian convoy near Kramatorsk on May 17th.

The question that should be asked is how it is possible that Ukrainian convoys get attacked so easily and deadly?