Two planes carrying bodies from crashed flight MH17 have landed in the Netherlands where a day of mourning for the 298 victims has been declared.
Experts there will begin to identify the dead, most of whom were Dutch.
Pro-Russian rebels have been widely accused of shooting down the Malaysia Airlines plane on 17 July.
UK government sources say intelligence shows rebels deliberately tampered with evidence, moving bodies and placing parts from other planes in the debris.
As fighting continued in eastern Ukraine on Wednesday, officials in Kiev told the BBC that two aircraft, thought to be military jets, had been downed just 35km (20 miles) from the crash site.
The officials had no information on the cause of the crashes, or the fate of the pilots.
Pro-Russian separatists probably shot down MH17 "by mistake", no link to Russia found - US intelligence http://t.co/WhY1Gd071a— BBC Breaking News (@BBCBreaking) July 22, 2014
US intelligence officials had earlier released evidence to the media that they said showed the separatists' involvement in bringing down flight MH17.
Rebels have also been accused of exaggerating the number of bodies transported from the crash site to the town of Kharkiv on Tuesday.
They had claimed 282 bodies had been loaded on to a train, but experts said only 200 could be verified.
The two military planes - one Dutch and the other Australian - carrying the first 40 coffins landed at Eindhoven air base to be met by members of the Dutch royal family, Prime Minister Mark Rutte and hundreds of victims' relatives.
Churches around the Netherlands rang their bells for five minutes before the planes landed, and flags of all the nations affected by the disaster have been flying at half mast.
In a solemn ceremony, the coffins were slowly loaded into a fleet of waiting hearses.
The bodies are being taken to the Korporaal van Oudheusden barracks south of the city of Hilversum for identification. Rutte said that process could take months.
The hearses then moved off in a procession with a motorcycle escort.
Earlier, the coffins had been loaded on to the planes by a military guard of honour at Kharkiv airport in eastern Ukraine.
Ambassadors, officials and soldiers gathered to see off the planes.
Australian government envoy Angus Houston said the ceremony was intended to give the victims the "respect and dignity they deserve" after a "tragedy of unspeakable proportions".
In a separate process, the "black box" flight-data recorders from MH17 have arrived in the UK, where they will be examined at the headquarters of the Air Accidents Investigation Branch in Farnborough.