Fighting between Ukrainian troops and rebels raged Thursday near the crash site of Malaysian flight MH17, as countries which lost 298 citizens in the disaster moved to deploy their police to secure the impact zone.

The Dutch team leading the crash probe was stuck in Kiev, unable to join a handful of international investigators at the rebel-controlled site.

Meanwhile, Ukraine's army reported four soldiers killed over the last 24 hours in its offensive to retake the eastern industrial heartland from the pro-Russian insurgents.

Planes carrying more bodies recovered from the MH17 crash site in Ukraine were flown to The Netherlands on Thursday.

Two planes carrying a total of 74 coffins landed at Eindhoven in the south of the country, from where they are to be taken to a military barracks in Hilversum, near Amsterdam, for forensic examination and identification. The Netherlands counts 193 citizens lost in the disaster.

In Brussels EU diplomats were also preparing to stiffen sanctions on Russia, which they allege is arming the Ukrainian separatists accused of bringing down the plane.

In eastern Kiev, investigators said human remains were still strewn amidst the debris of the wreck, where recovery work has been at a standstill since Tuesday. Dutch authorities said they can only be sure that 200 corpses have been recovered out of the 298 people killed on board.

Announcing that Australia was ready to deploy police to secure the debris zone, Prime Minister Tony Abbott said that there was still a need for a rigorous search of the site.

"On the site it is still clear that nothing is happening without the approval of the armed rebels who brought the plane down in the first place," he said.

"There has still not been anything like a thorough professional search of the area where the plane went down, and there can't be while the site is controlled by armed men with vested interest in the outcome of the investigation."

Abbott, whose country lost 28 citizens, said 50 Australian officers were on standby in London.

The Dutch cabinet meanwhile is working on a new UN resolution for an armed mission to secure the crash site, sources told national news agency ANP.

Rebels and government forces have declared a ceasefire in the immediate vicinity of the site, but just beyond, fierce fighting was ongoing.

The Ukrainian military said rockets were on Thursday being fired "from the Russian side," hitting locations close to Lugansk airport and in several areas in the Donetsk region.

Mortar shells also rained down on Avdiyika in Donetsk region, the army said, without giving details of casualties.

Meanwhile, the Red Cross warned both sides to abide by the Geneva Conventions, declaring that it considered Ukraine to be in a state of civil war.

Ukrainian Prime Minister Arseny Yatseniuk tendered his resignation on Thursday to parliament after upbraiding politicians for failing to pass laws on energy and on the budget to increase financing for the army.

"I announce my resignation in connection with the collapse of the coalition and the blocking of government initiatives," he told parliament.

In Brussels, the EU was looking at punishing Russia, which it accuses of fanning the rebellion in Ukraine's east by arming the separatists.

Reports said Thursday that the EU may go even further than the United States in hitting Russian banks with sanctions over the Ukraine crisis, curbing their ability to raise fresh funds.

If imposed, the sanctions would come just a week after the last round was unveiled by both the US and the EU against Moscow.

The International Monetary Fund spokesman William Murray warned Thursday at a news conference that recent sanctions against Russia, "especially those that have been imposed by the United States," signaled a step-up of geopolitical tensions and "could have a significant adverse impact on the Russia economy" and ripple through the region.