Fresh fighting in eastern Ukraine has forced an international forensics team to halt operations in part of the vast crash site of Malaysian flight MH17.
Observers had to withdraw from one village when they heard artillery fire although work is still continuing across much of the area.
MH17 went down on 17 July with the loss of all 298 passengers and crew.
The US and Ukraine say pro-Russian rebels probably shot down the jet with a missile but rebels deny the claim.
Alexander Hug, the deputy chief monitor with the Ukraine mission of the Organisation for Security and Cooperation in Europe (OSCE), told Agence France-Presse a visit to the village of Petropavlivka had been agreed with the rebels and Ukrainian forces.
However, he said: “We heard at a distance of approximately two kilometres incoming artillery from where we were and that was too close to continue.”
However, the BBC’s Jonathan Beale, at the crash scene, says there has been no fighting at the main site and the experts have been able to do their work
About 70 Dutch and Australian experts are scouring a site of some 20 sq km.
A spokesman for the Dutch team said it was still focusing on searching for human remains, although security is also a key issue.
Neither the rebels nor Ukrainian forces are in full control of the site.
The Dutch team has flown in from the Netherlands two dogs trained to search for human remains and another two specialist dogs are on their way from Belgium.
Our correspondent says the Australian team also has specialist equipment – a mini-drone fitted with a camera – but it has not yet been given permission by the rebels to fly it.
The US and Ukraine say pro-Russian rebels probably shot down the plane with a missile supplied from Russia.
The rebels say it could have been brought down by a Ukrainian fighter jet.
Most of those who died were Dutch nationals.
More than 220 coffins have now been sent back to the Netherlands.
Separately, a senior adviser to the rebels confirmed that extrajudicial killings had been carried out in eastern Ukraine “to prevent chaos”.
Igor Druz told the BBC such “executions” sent an important signal to the rest of the rebel forces.
Druz told the BBC: “On several occasions, in a state of emergency, we have carried out executions by shooting to prevent chaos. As a result, our troops, the ones who have pulled out of Sloviansk, are highly disciplined.”
Sloviansk was a key rebel stronghold before it was recaptured last month by Ukrainian government forces.
Druz said the rebels wanted to establish a socially responsible state that would protect Christian values.
He also said the Ukrainian government was “totally illegitimate”.
Druz said: “These people have come to power by committing murders and staging an armed coup. Now they are committing war crimes. They are bombing our cities. They shell cities and then blame it on our fighters. This is nonsense.”
More than 1,500 people are believed to have been killed in the conflict which erupted in east Ukraine in April, after rebels declared independence from the new government in Kiev.
Russia, which annexed Ukraine’s Crimea region in March, has been accused of arming the rebels and has been targeted by US and EU sanctions