KIEV, Ukraine (KABC) --Senior U.S. intelligence officials say they have no evidence of direct Russian government involvement in the shooting down of Malaysia Airlines Flight 17 in Ukraine.
Intelligence officials believe the passenger jet was likely felled by an SA-11 surface-to-air missile fired by Russian-backed separatists in eastern Ukraine and that Russia "created the conditions" for the downing by arming the separatists.
The air disaster killed all 298 people on the plane. It has been a slow process, but the majority of the victims' remains will soon be back in their home country.
A train packed with the bodies of the victims arrived Tuesday in Kharkiv, a government-controlled city where Ukrainian authorities have set up their crash investigation center. From there, the victims' remains will be flown to the Netherlands.
The Dutch government has declared Wednesday a day of national mourning as the country prepares for the arrival of the first bodies.
Family members of Malaysians who were aboard Flight 17 have given blood samples to government health officials and police forensic experts. The samples are expected to be sent to Amsterdam to help identify the remains and bodies of the victims.
The crash site itself, in farmland held by the pro-Russian separatists, remained unsecured five days after the disaster - another source of frustration for officials around the world eager to establish what happened.
The European Union agreed to impose new sanctions against officials deemed responsible for Russia's actions in Ukraine. The Lithuanian foreign minister blamed "terrorists supplied by Moscow" for the airliner's destruction.
Pro-Russian rebels in eastern Ukraine have finally handed over the flight data recorders to Malaysian officials. The rebels say they believe the black boxes will reveal the truth, but analysts say the black boxes likely won't indicate who shot the plane down and why.
Rebels continue to deny responsibility, and Russia denies any involvement in the disaster. They say a Ukraine SU bomber was near the jetliner and could have shot it down.
Russian media outlets are spreading theories that perhaps Ukraine shot down the plane because it thought the jet was President Vladimir Putin's official aircraft.
The Associated Press contributed to this report.
PHOTOS: Malaysia Airlines Flight MH17 crashes