Heavy fighting between the Ukrainian military and pro-Russia separatists has prevented an international police force from reaching the crash site of Malaysia Airlines flight MH17.

The force are attempting to reach the site to secure the remaining evidence so that the wreckage and any human remains can be examined by plane crash investigators.

Meanwhile, a Ukrainian official claimed on Monday that MH17’s black box data recorders show the plane crashed because of “massive explosive decompression” from a rocket strike.

Flight MH17 crashed in eastern Ukraine on 17 July, killing all 198 people on board.

The West blames the crash on pro-Russia rebels, who they claim shot down the plane with a Soviet-built BUK SA-11 “Gadlfy” missile system, believing it to be a Ukrainian military aircraft.

UN High Commissioner for Human Rights Navi Pillay has described the downing of the plane as a “violation of international law” and a possible war crime.

The most recent UN report on hostilities in the region states that at least 1,129 people have been killed and 3,442 injured in three months of fighting in eastern Ukraine. More than 200,000 have fled their homes, with many crossing the border into Russia.