Kiev , Ukraine ( CNN ) -- Did a Russian fire the missile that downed Malaysia Airlines Flight 17 ? That depends on who you ask . A top Ukrainian official says he has no doubt . Vitaly Nayda , Ukraine 's director of informational security , told CNN the person who shot down the flight was `` absolutely '' a Russian . `` A Russian-trained , well-equipped , well-educated officer ... pushed that button deliberately , '' he said . `` We taped conversations '' between a Russian officer and his office in Moscow , Nayda said . `` We know for sure that several minutes before the missile was launched , there was a report '' to a Russian officer that the plane was coming , he said . `` They knew the plane was coming with constant speed , in constant direction , '' and should have known it was not a fighter jet but `` a big civilian plane , '' he said . U.S. officials say pro-Russian rebels were responsible for shooting down Malaysia Airlines Flight 17 , but they now believe it 's likely the rebels did n't know the plane was a commercial airliner when they opened fire , U.S. intelligence officials said Tuesday . The officials have determined that Russia bears some responsibility for the incident because of its support for the rebels , but they have n't been able to determine exactly who fired the missile , whether Russian military were at the site or whether the Russians were directly responsible for launching the missile . Moscow has denied claims that it pulled the trigger . And Russian Army Lt. Gen. Andrei Kartapolov suggested a Ukrainian jet fighter may have shot the plane down . Ukrainian President Petro Poroshenko rejected that in an exclusive interview with CNN , saying that all Ukrainian aircraft were on the ground at the time . Vitaly Churkin , Russia 's ambassador to the United Nations , was asked Monday about different intercepted recordings , purportedly of pro-Russian rebels talking about shooting down a plane . Churkin suggested that if they did , it was an accident . `` According to them , the people from the east were saying that they shot down a military jet , '' he said . `` If they think they shot down a military jet , it was confusion . If it was confusion , it was not an act of terrorism . '' Pro-Russian rebels have repeatedly denied responsibility for the attack . At crash site , an eerie calm . Now that rebels have handed over the black boxes and the bodies of victims killed when Flight 17 went down , the crash site in eastern Ukraine was eerily quiet on Tuesday , a spokesman for observers in the area said . There were no more local emergency workers or teams combing the wreckage -- even though Dutch officials said they were n't sure whether the remains of all the victims had been recovered . `` They had even taken down the tents , '' said Michael Buciurkiew , spokesman for the monitoring mission from the Organization for Security and Cooperation in Europe . `` There was no activity whatsoever . ... We had an internal discussion today on whether to say it 's already trending towards a cleanup operation . There 's no active recovery of remains going on right now . '' As investigators arrive at the scene , it 's unclear what evidence they 'll find . Before activity died down at the site , Buciurkiew said , observers saw emergency workers moving around wreckage . `` Major pieces of the fuselage have been moved , '' he said . At one point , he said , observers witnessed teams at the scene `` taking out diesel-powered saws and sawing quite invasively into the cockpit . '' Dutch PM : Identifying bodies could take months . A train carrying the remains of crash victims arrived in Kharkiv , Ukraine , on Tuesday . Investigators were going through the train cars and transferring bodies to a factory , where a facility was set up to transfer them to coffins and get them on a military plane to the Netherlands for forensic investigation . But officials offered conflicting reports about how many bodies were on the train , with a top Dutch official expressing concern that the remains of more victims could still be at the crash site . Malaysian official Mohd Sakri , who traveled on the train with the remains , said there were 282 corpses and 87 body parts aboard -- the same tally Ukrainian officials earlier gave to describe the remains recovered from the crash site . But Dutch investigators only confirmed there were at least 200 bodies transported from the crash site , Jan Tuinder , head of the Dutch delegation , told reporters . Another Dutch official said investigators were still going through the train cars and it was possible all the crash victims were on the train . There were 298 people aboard the plane when it crashed . Dutch Prime Minister Mark Rutte said he expects the first plane carrying the remains to arrive Wednesday in Eindhoven . As soon as the remains are identified , families of the victims will be informed . In some cases , that could happen quickly , Rutte said , but in other cases , identification could take weeks or even months . Frans Timmermans , the Dutch foreign minister , said bringing the victims ' remains home is his country 's top priority . `` To my dying day , I will not understand that it took so much time for the rescue workers to be allowed to do their difficult jobs , '' he told the U.N. Security Council on Monday , `` and that human remains should be used in a political game . '' What 's next in the investigation ? Ukrainian rebels handed over the so-called black boxes Tuesday after what Malaysian officials said were repeated attempts to negotiate with the rebels . `` In recent days , we have been working behind the scenes to establish contact with those in charge of the MH17 crash site , '' Malaysian Prime Minister Najib Razak said Monday . But the handover is only the beginning . British Prime Minister David Cameron tweeted that Britain agreed to a Dutch request for accident investigators at Farnborough , southwest of London , to retrieve data from the boxes for international analysis . And the U.S. National Transportation Safety Board said one of its experts will help retrieve information from the black boxes . The voice recorder could include audio from the cockpit , which would show whether the pilots knew the plane had been hit , said Mary Schiavo , a CNN aviation analyst and former inspector general for the U.S. Department of Transportation . And the flight data recorders will give investigators information about engine settings , pressurization and electronic communications , among other details , she said . But even the black boxes might not answer the two most pressing questions : who shot down the plane and why . U.S. and other officials have said it appears the plane was shot down by a sophisticated surface-to-air missile in rebel-held territory . Evidence supporting that conclusion includes telephone intercepts and video of a Buk missile launcher traveling into Russia with at least one missile missing . U.S. President Barack Obama , Cameron and others have said the pro-Russian rebels could not have shot down such a high-flying jet without weapons and training from Russia . Obama called on Russia to rein in the rebel fighters , who he said had treated remains poorly and removed evidence from the site . `` What exactly are they trying to hide ? '' he said . Russian President Vladimir Putin said Tuesday that his country would use its influence with Ukrainian rebels to push for a full investigation , the Reuters news agency reported . But those assurances did little to stem efforts to crack down on the rebels and their supporters . The European Union 's Foreign Affairs Council agreed Tuesday to establish a new list of entitles and individuals , including some from Russia , to face EU sanctions . Timmermans said the Netherlands would seek sanctions involving various fields , including defense , high technology , the energy sector and financial services . A brawl broke out Tuesday in Ukraine 's parliament , where fighting takes place frequently , as lawmakers voted to increase the number of troops battling pro-Russian rebels . Nikolai Levchenko , who is from the Donetsk region and has been noticed at separatist rallies , accused the government of killing its own people . A nationalist lawmaker then ran up to him . Soon many lawmakers swarmed around them , with some apparently trying to break up the fight . Ukraine opens criminal case . The U.S. government has released a map of what it says was the flight 's path and the site from which the missile was fired . It also released images that it said showed a weapons buildup at a Russian training facility near the Ukraine border . As Ukraine ratcheted up accusations that Moscow was involved in downing the plane , it also opened criminal cases against Russia 's defense minister and a Russian businessman , calling both `` accomplices of terrorists . '' The Ukrainian Internal Affairs Ministry accused Russian Defense Minister Gen. Sergei Shoigu of helping form `` illegal military groups '' in the Donetsk region , where pro-Russian rebels have declared their own government . `` The illegal military groups , which are led by citizens of the Russian Federation , make regular attacks on government institutions and other organizations that have led to multiple human deaths , destruction and other consequences , '' the ministry said in a statement . And the ministry accused Russian billionaire Konstantin Malofeev of financing the `` illegal military units . '' Russian officials have repeatedly denied involvement in fomenting violence in the region . A June profile on Malofeev by Bloomberg News noted that the `` self-proclaimed head of the unrecognized Donetsk People 's Republic and its rebel army leader have both worked for Malofeev , though the financier denies any role in the unrest . '' Earlier this month , Ukraine opened a criminal case against the head of Russia 's Border Service . The ministry 's statement Tuesday contained no specific references to the downing of Malaysia Airlines Flight 17. Who are Ukraine 's pro-Russian rebels ? Ukrainian President : The world must choose sides . So much we do n't know -- five unanswered questions . Who were the victims ? Should jet have flown over Ukraine ? CNN 's Kyung Lah reported from Kiev ; Josh Levs and Catherine E. Shoichet reported from Atlanta ; and CNN 's Nick Paton Walsh , Holly Yan , Carol Jordan , Pamela Boykoff , Phil Black , Gul Tuysuz , Elizabeth Joseph , Stephanie Halasz , Antonia Mortensen , Barbara Starr and journalist Victoria Butenko contributed to this report .
NEW : It 's unclear how much of a role Russia played , U.S. intelligence says . The European Union agrees on a plan for new sanctions to include Russia . Ukraine opens criminal cases against Russian defense minister and businessman . Dutch official : At least 200 bodies were on the train ; more could be at crash site .