GRABOVE, Ukraine: Heavy shelling around the crash site of downed Malaysian flight MH17 forced Dutch and Australian police to scrap a planned trip on Sunday, as 13 people including two children were killed during clashes in insurgent-held east Ukraine.

The unarmed contingent of law enforcement officers were due to head to the location 10 days after the disaster following a deal with rebels aimed at allowing a long-delayed probe to go ahead.

But international observers overseeing the trip had to abruptly ditch their plans after clashes shattered a supposed truce between government forces and insurgents in the area around the site, where some remains of the 298 victims still lie decomposing under the summer sun.

“There is fighting going on. We can’t take the risk,” said Alexander Hug, deputy chief monitor of the European security body OSCE’s special mission in Ukraine.

“The security situation on the way to the site and on the site itself is unacceptable for our unarmed observer mission,” he told reporters in the insurgent stronghold Donetsk, the biggest city in the region.

An AFP photographer heard artillery bombardments just a kilometer from the rebel-held town of Grabove next to the crash site and saw black smoke billowing into the sky.

Terrified local residents were fleeing and checkpoints controlled by separatist fighters were abandoned.

The Dutch Justice Ministry confirmed that security advisers had also halted a trip by a team of forensic experts.

“Because of fighting in the area, the situation is still too unstable to work at the crash site,” the ministry said in a statement.

Earlier Australian Prime Minister Tony Abbott said 49 officers from the Netherlands and Australia — which together lost some 221 citizens in the crash — were due at the scene Sunday and that there would be “considerably more on site in coming days.”

That came after Malaysian Prime Minister Najib Razak said he had reached an agreement with the pro-Russian insurgents controlling the site to allow the police deployment.