Dutch experts working in rebel-controlled eastern Ukraine have recovered more human remains at the crash site of Malaysian Airlines flight 17 as they began collecting debris.

The remains of 289 victims had been previously identified, but nine bodies were still lost. The latest remains were only discovered now because they had been damaged by fire during the crash, an observer with the Organisation for Securtiy and Co-operation in Europe said on Ukrainian television.

Experts reportedly retrieved one part of the plane’s landing gear and a large piece of its fuselage from the crash site. The recovered fragments are to be loaded on trains and taken to the government-controlled eastern Ukrainian city of Kharkiv. The investigation into the cause of the crash is being conducted there and in the Netherlands.

All 298 people aboard the Boeing 777 flying from Amsterdam to Kuala Lumpur were killed when it was shot down on 17 July over a rebel-held area. Charred remains of the aircraft are scattered across fields covering an area of 20 sq km.

Efforts to conduct investigations and recovery operations have been delayed amid continued fighting between government troops and separatist fighters. A truce was agreed in September, but hostilities have raged on nonetheless.

A new video from the crash site moments after the plane went down also surfaced on Sunday showing locals trying to gather buckets of water to pour on burning debris. The video was apparently filmed in Hrabove, one of the towns where debris from the plane fell. In the video, one resident can be heard in the background saying “a rocket was fired.”

Kiev and the West suspect that a Buk surface-to-air missile brought down the plane, while the Russian authorities have argued that a Ukrainian fighter jet shot it down. At the end of the G20 meeting in Australia, president Barack Obama said Western sanctions against Russia would continue, although he said additional ones would not be adopted for the time being. Obama accused Moscow of continuing to provide arms to pro-Russian rebels in eastern Ukraine.

“We’re also very firm on the need to uphold core international principles, and one of those principles is you don’t invade other countries or finance proxies and support them in ways that break up a country that has mechanisms for democratic elections,” Obama told reporters.

The Australian prime minister, Tony Abbott, has been particularly critical of Russia since the Malaysia Airlines plane was shot down. Abbott said he and Putin had engaged in a “very robust” discussion about the situation in Ukraine.

“I utterly deplore what seems to be happening in eastern Ukraine,” Abbott said. “I demand that Russia fully cooperates with the investigation, the criminal investigation of the downing of MH17, one of the most terrible atrocities of recent times.”

Also on Sunday, a new humanitarian convoy of more than 70 trucks from Russia arrived in Luhansk, the seventh such convoy to be dispatched. A video from the pro-Russian ANNA news agency showed the convoy driving down the highway flying the flags of Russia and the emergencies ministry.

At least nine fuel trucks could be seen in the video, and another segment showed emergencies ministry workers unloading barrels with the logo of Russian state oil champion Rosneft on the side from other trucks. A pickup truck at the head of the convoy had a black Russian military license plate.

Three government soldiers were killed just north of Luhansk in Stanitsa Luhanska in what Ukraine’s interior ministry said was a separatist attack.