MOSCOW - President Vladimir Putin said on Tuesday Russia would use its influence with separatists in east Ukraine to allow a full investigation into the downing of a Malaysian airliner, but said the West must put pressure on Kiev to end hostilities.Putin also called on Western powers not to meddle in Russia’s domestic affairs and said steps were needed to strengthen the country’s military capabilities because of moves by NATO and to protect the economy from “external threats”.“We are being called on to use our influence with the separatists in southeastern Ukraine. We of course will do everything in our power but that is not nearly enough,” Putin said at the start of a meeting with defence and security chiefs. “Ultimately, there is a need to call on the authorities in Kiev to respect basic norms of decency, and at least for a short time implement a ceasefire,” he said.Putin’s comments were his first detailed response in public to Western criticism of Russia’s role in Ukraine since the Malaysian airliner was brought down on Thursday, killing 298 people.Reading from notes at the head of a long table with officials seated on each side, Putin spoke much more forcefully than during brief televised remarks on the plane’s downing first released in the early hours of Monday, when he had seemed less assured than usual.Putin reiterated his belief that protests that toppled Ukraine’s former Russian-backed leader were instigated and funded from abroad.Despite Western sanctions, he said Moscow would stand by separatists in eastern Ukraine whom, he described as part of a popular rising against an illegal coup.“Russia is being presented with what is almost an ultimatum: ‘Let us destroy this part of the population that is ethnically and historically close to Russia and we will not impose sanctions against you,” Putin said. “This is a strange and unacceptable logic.”He did not, however, directly address the question of whether Russia has been arming the rebels - he has denied such accusations before.Rebels controlling the crash site of Malaysian flight MH17 on Tuesday handed over the plane’s black boxes, and declared a localised truce to allow international experts full access to the forensic minefield in east Ukraine.Dutch investigators leading a probe into the disaster were preparing to take charge of the bodies of 280 victims set to arrive by train in the government-controlled city of Kharkiv. Ukrainian troops on Tuesday wrested back control of the strategically-important town of Severodonetsk from pro-Russian rebels in eastern Ukraine, the interior ministry said.Ukraine’s security forces were in control of “all the vital facilities” in the city of around 110,000, located roughly 120 kilometres (75 miles) to the north of the key rebel stronghold of Donetsk, the ministry said in a statement. The remains are to be taken to the Netherlands which had 193 citizens on board when the flight went down on Thursday, a disaster that has taken Ukraine’s bloody three-month conflict to the doorstep of countries as far away as Malaysia and Australia.Pro-Russian separatists - who stand accused of downing the aircraft, possibly with a missile supplied by Moscow - conceded to a furious international clamour for the bodies and black boxes to be released to investigators.The rebel concessions came as European foreign ministers were to meet in Brussels to weigh possible new sanctions against Russia for its perceived support of the insurgency rocking ex-Soviet Ukraine.Both black boxes, which record cockpit activity and flight data, were handed to Malaysian officials by the prime minister of the self-proclaimed Donetsk People’s Republic, Alexander Borodai, in front of scores of journalists.Borodai also announced a ceasefire within 10 kilometres of the site, hours after the pro-Western authorities in Kiev said they would halt all fighting in the zone.His rebel forces had Monday had allowed Dutch forensic experts to examine the bodies, kept in refrigerated train cars away from the sweltering summer heat. International monitors were also finally given freedom to examine the vast crash site, littered with poignant fragments from hundreds of destroyed lives.Australian Prime Minister Tony Abbott, whose country lost 28 citizens and nine residents in the crash, said: “There is still a long, long way to go.”“After the crime comes the cover-up,” he added. “What we have seen is evidence tampering on an industrial scale. That has to stop.”The struggling airline meanwhile had to defend itself late Monday after confirming it had diverted a flight from Ukrainian to Syrian airspace. “The Syrian airspace was not subject to restrictions,” the flag carrier said in a statement.In Brussels, European foreign ministers were meeting to discuss possible new sanctions against Russia, which has been accused by the United States of supplying the missile allegedly used to shoot down the plane.Obama put the onus on Moscow to lift the suspicions weighing upon it, saying President Vladimir Putin must prove “that he supports a full and fair investigation”.An under-fire Moscow hit back, saying records showed a Ukrainian military plane was flying three to five kilometres from the Boeing 777 before it crashed.“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.Ukraine’s President Petro Poroshenko dismissed the suggestion the army was to blame, calling it an “irresponsible and false statement” by Russia.Russia’s riposte came after Kiev released fresh recordings of what it said were intercepted conversations between rebels conspiring to hide the flight’s black boxes from international monitors.The US embassy confirmed as authentic earlier recordings 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.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 goal many in the Russian-speaking east do not share.