At least 10 government troops have been killed in an ambush by pro-Russian separatists in an area near the wreckage of Malaysia Airlines Flight 17, Ukrainian authorities said yesterday.

However national television put the number of dead at 20 and said a Grad missile had been used by pro-Russian rebels in the attack.

“It is known that 14 people died but the bodies of four of them have not been identified and could be Ukrainian soldiers or terrorists,” said Kiev military spokesman Oleksiy Dmytrashkivsky.

Defence officials said that the attack happened during a redeployment in the town of Shakhtarsk, which has been the object of sustained battles for several days.

The Ukraine military said it was relaunching a broader offensive against the rebels following a day-long ceasefire but they insisted troops would not carry out operations in the immediate vicinity of the site.

Spokesmen claimed Kiev forces had taken the village of Novyi Svit from rebels and begun operations to secure the volatile border with Russia.

Both sides in the conflict in east Ukraine have tentatively agreed to a ceasefire around the crash zone, although fighting was still being reported in nearby locations.

International inspectors nonetheless set off for a second day at the crash site.

A 60-strong team travelled in a 16-vehicle convoy from their base in the rebel stronghold of Donetsk, but on a road that didn’t go through Shakhtarsk. 

The convoy was joined by three vehicles from the International Committee of the Red Cross when it reached the government-controlled town of Debaltseve.

Clashes along routes to the wreckage site had previously kept investigators from reaching the area to find and retrieve bodies that have been decaying in the midsummer heat.

Ukrainian forces have latterly focused their strategy on driving a wedge into an area between the largest rebel-controlled cities.

Shakhtarsk lies on one of two highways linking Donetsk and Lugansk and is about 12 miles south of the site where the Malaysia Airlines plane came down.

It is believed up to 80 bodies still remain at the site.