Torez, Ukraine: Dutch forensic experts on Monday were examining bodies from the MH17 plane disaster being held an east Ukraine train station as Kiev and insurgents wrangled over the fate of the remains.

As world leaders deplored the “shambolic” state of the crash site left in the hands of the rebels and accused Russia of supplying the weapons allegedly used to shoot down the passenger jet, Moscow hit back and sought to shift the blame to Kiev.

The UN Security Council is expected to adopt an Australia-backed resolution demanding pro-Russian separatists grant unrestricted access to the crash site to international experts when it meets at 1900 GMT.

European leaders have signalled they could ramp up sanctions against Russia as early as Tuesday — barely a week after the last round of toughened embargoes.

Whole sectors of the economy including goods with possible military uses could be targeted, British Prime Minister David Cameron said.

The separatists’ violent bid to join Russia is the latest chapter in a prolonged crisis sparked by Kiev’s desire for closer ties with the EU — a sentiment many in the Russian-speaking east do not share.

On the ground, the animosity between Ukraine’s warring sides was underlined by intense shelling which erupted in the rebel stronghold of Donetsk, a city just 60km from the station where the bodies are being held in refrigerated wagons.

Four people were killed and terrified civilians fled, as Ukraine President Petro Poroshenko quickly ordered his troops to hold fire within a 40km radius around the crash site, where forensic experts were heading.

Russian President Vladimir Putin, the target of global ire for failing to use his influence to rein in the pro-Russian rebels, appeared to adopt a conciliatory tone Sunday, saying Moscow would do “everything in its power” to resolve the three-month-old Ukrainian conflict.

But on Monday, Moscow moved to slap down accusations by US Secretary of State John Kerry who had said the missile system used to shoot down the aircraft was transferred from Russia to separatists.

A senior Russian defence ministry official insisted that “Russia did not give the rebels Buk missile systems or any other kinds of weapons or military hardware”.

Instead Moscow challenged Kiev, saying records show a Ukrainian military plane was flying just three to five kilometres from the Boeing 777 before it went down on Thursday, killing all 298 people on board.

“With what aim was a military plane flying along a civilian aviation route practically at the same time and at the same flight level as a passenger liner?” asked Lieutenant-General Andrei Kartopolov.

Moscow’s riposte came after Kiev released fresh recordings of what it says are intercepted conversations between rebels conspiring to hide the flight’s black boxes from international monitors.

And the US embassy confirmed as authentic recordings released earlier by Kiev of an intercepted call between an insurgent commander and a Russian intelligence officer as they realised they had shot down a passenger jet.

The Washington Post said Ukraine’s counterintelligence chief had photographs and other evidence that three Buk M-1 anti-aircraft missile systems moved from rebel-held territory into Russia less than 12 hours after the crash.