An international police team has failed to reach the crash site of a Malaysian Airlines plane for a second day running as clashes rage in a town on the road to the area.
A delegation of Australian and Dutch police and forensic experts stopped Monday in Shakhtarsk, a town around 30 kilometres from the fields where the aircraft was downed.
Sounds of regular shelling could be heard from Shakhtarsk and residents were fleeing town in cars.
AP reporters saw a high-rise apartment block in the town being hit by at least two rounds of artillery.
Meanwhile, analysis of the black box flight recorders from the downed airliner show it was destroyed by shrapnel coming from a rocket blast and went down because of ‘‘massive explosive decompression‘‘, a Ukrainian security official said on Monday.
The spokesman for Ukraine’s Security Council, Andriy Lysenko, told a news conference in Kiev the information came from experts analysing the recorders from the plane that came down in rebel-held territory in eastern Ukraine on July 17.
Britain was tasked with downloading the data from two black boxes recovered from the crash site and handing that information over to international investigators for analysis.
Kiev and the West accuse pro-Russian rebels of shooting down the plane. Moscow says the Ukrainian government is responsible for the crash, which killed all 298 people on board.
Evidence could be lost if fighting continued, said Australia's Deputy Commissioner of National Security Andrew Colvin, and the chances of finding the remains of all 298 dead grew slimmer as time passed.
Before the latest fighting, Colvin said: ''The fighting intensified overnight. Whether the intensification diminishes over coming days and creates a more permissive environment, it may be as early as today that we say that fighting has diminished enough to go back in.''
Colvin said after assessing the risks, he believes it is safe to send Australian Federal Police (AFP) officers into the crash site - which has now become a battleground for Ukrainian and the Russian backed rebels.
Clashes overnight between Ukrainian troops and pro-Russian rebels killed at least 13 people.
The unarmed Australian and Dutch team of police investigators, guided by the Organisation for Security and Cooperation in Europe (OSCE), which has already made a short visit to the site, needed to be assured of a sizeable window of time at the site to complete the probe, Colvin said.
''We don't want to put our officers in danger for the sake of a brief look at the site,'' he said. ''We've had a look at the site already... the next stage of this is to get in and start the examination.''
Asked if he was "comfortable" with sending his officers into the area unarmed, the deputy commissioner said the mission was new territory for the AFP.
"Comfortable is a broad word, no we can't be comfortable but we have ... dealt with the risks to a point where we wouldn't send our people into a situation where we didn't think they would be safe," he said.
Colvin said while the AFP had responded to disasters, terrorist attacks and conflicts in the past, they had never done so without weapons.
"We haven't deployed in a conflict zone in this manner before," he said.
"We've said all along that this is a risky mission but we are working on the basis that if it's a permissive environment we will go in, if it's a permissive environment those risks are reduced."
A top AFP officer has admitted he is not comfortable with deploying unarmed Australian officers to the site of the downed flight.
Colvin acknowledged that it could be some time before the team gained access to the crash site.
''There remains a possibility that we may not get there in the near future,'' he said. ''I don't want to consider the fact that we may never get to that site.''
Ukraine said on Sunday it was trying to dislodge the rebels, but denied it was fighting near the crash site, saying the separatists had put the monitors off by falsely claiming the army was operating nearby.
Even when access is gained, officers are preparing for the possibility that not all human remains will be recovered.
The 49-person mission that includes 11 AFP officers is waiting for the go-ahead in the rebel-held city of Donetsk.
Colvin warned of the difficult circumstances the mission faces, including the size of the crash scene, trauma to the bodies of victims, and complications gaining access to the site almost two weeks after the Malaysia Airlines plane was brought down by a surface-to-air missile.
''We have to prepare ourselves for the possibility that not all remains will ultimately be recovered,'' he said.