Ukraine on July 31 announced a day-long pause to its military operation against pro-Russian separatists in the east.
A military spokesman said the move was in response to an appeal by UN Secretary-General Ban Ki-moon to halt fighting to allow access to the crash site of the Malaysian airliner.
All 298 people on board were killed when the plane came down on July 17, allegedly shot down by pro-Russian separatists.
A team of Australian and Dutch police and crash investigators has tried for four days to make its way from Donetsk to the crash site but has had to turn back because of fighting between Ukrainian forces and the separatists.
Australian Foreign Minister Julie Bishop has told Australian broadcaster ABC that there could still be as many as 80 bodies at the crash site.