Dutch police heading up the international probe into the downing of Malaysia Airlines flight MH17 said that the situation around the crash site remains perilous, despite a small team managing to access the scene.
Earlier, Dutch and Australian experts accompanied by a team of international monitors reached the crash site.
Their visit comes after days of fierce fighting had stopped them reaching the area in eastern Ukraine.
"Monitors reach MH17 crash site for first time in almost week, accompanied by 4 Dutch, Australian experts. Used new route to access," the Organisation for Security and Cooperation in Europe said on Twitter.
The monitoring mission is in charge of facilitating the international investigation into the crash.
The plane went down on 17 July, killing all 298 people on board.
Russian experts also aim to visit the site to examine the debris together with international investigators.
"Russian experts intend to meet the head of the investigative commission ... and hand over all the materials that the chairman of the commission had previously asked for," Russia's Federal Air Transport Agency said.
"Today, the Russian representatives will also try to reach the crash area of the Boeing-777 and together with specialists from the international investigative commission examine the state of parts of the aircraft at the site."
Although most of the bodies have been recovered from the site, there are still human remains and personal belongings to be secured.
Meanwhile, the Ukrainian parliament has rejected the resignation of Prime Minister Arseny Yatsenyuk.
It means he will remain at the helm of the troubled country, despite announcing his resignation last week in protest at the collapse of his ruling coalition.