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The first of hundreds of simple wooden coffins bearing the bodies of Malaysia Airlines Flight 17 passengers arrived in The Netherlands Wednesday, where investigators face the grim task of identifying those killed when the plane was shot down over Ukraine six days ago.

The bodies were taken by refrigerated rail earlier in the week to Kharkiv, then flown out of Ukraine by two military transport aircraft, one Dutch and one Australian, following a brief farewell ceremony.

A Dutch Hercules C-130 that Dutch government spokesman Lodewijk Hekking said was carrying 16 coffins was closely followed by an Australian C-17 Globemaster plane carrying 24 coffins.

"Think of all the people who were flying away on holiday, all the young people who had just finished their final school exams," Jikkie van der Giessen, of Amsterdam, told Reuters. "They were looking fully toward the future and then you're shot down. Whether it was an accident or on purpose, the fact is it's horrible."

The remains arrived Wednesday afternoon at an air base in the city of Eindhoven. The flights were met by Dutch King Willem-Alexander, Queen Maxima, Prime Minister Mark Rutte and other government officials.

Hundreds of relatives were also there, according to government spokesman Lodewijk Hekking. He said the planes carried 40 coffins in all.

Churches across the country rang their bells for five minutes before the planes landed, while flags of all the nations who had victims in the disaster were flown at half-mast at the air base, the BBC reported.

A military honor guard stood to attention while a trumpeter played The Last Post, a military song for people killed in war, according to Reuters.

After a moment of silence across the nation, soldiers and Marines boarded the planes and slowly unloaded the bodies and moved them into a fleet of waiting hearses.

The bodies are scheduled to be taken to a military barracks in the city for identification, a process that Rutte has said could take months.

At Schiphol Airport, where Flight 17 departed, mourners paid their respects by laying down hundreds of flower bouquets.

For one grieving mother, the arrival of the bodies marked a new stage of mourning and brought to an end the pain of seeing television images of victims lying in the undulating fields or in body bags being loaded into a train.

"If I have to wait five months for identification, I can do it," Silene Fredriksz-Hoogzand, whose son, Bryce, and his girlfriend Daisy Oehlers died in the crash, said before setting off for Eindhoven. "Waiting while the bodies were in the field and in the train was a nightmare."

The Dutch government has declared Wednesday a national day of mourning. Of the 298 victims of the plane crash, 193 were from the Netherlands.

Before departing on a trip to the West Coast Tuesday, President Barack Obama signed a condolence book at the Dutch Embassy in Washington.

Britain's Air Accidents Investigation Branch said Wednesday that Dutch authorities had delivered the plane's two "black boxes" to the agency's base at Farnborough, southern England, where information from the data and voice recorders will be downloaded.

Dutch investigators said the voice recorder was damaged but not manipulated, and its data is still intact.

The Dutch Safety Board said the information on the recorder will now be studied. Investigators will start Thursday studying the other recorder, containing flight data.

The board also announced that it will lead an international team of 24 investigators at the crash site and said unhindered access is critical.

"At the moment, there are no guarantees for the investigators' safety" at the scene, the board said, adding that it "and other parties" are working to get access to the site and to secure it.

Wreckage of the Boeing 777 fell on territory controlled by pro-Russian separatists who have been battling the Kiev government since April. U.S. officials say the plane was probably shot down by a missile, most likely by accident.

The European Union on Tuesday imposed sanctions against more Russian individuals but refrained from targeting entire sectors of the Russian economy while waiting for clearer evidence of Moscow's role in the Flight 17 disaster.

Senior U.S. intelligence officials said Tuesday that Russia was responsible for "creating the conditions" that led to the crash, but they offered no evidence of direct Russian government involvement.

The officials, who briefed reporters Tuesday under ground rules that their names not be used, said the plane was likely shot down by an SA-11 surface-to-air missile fired by Russian-backed separatists in eastern Ukraine. The officials cited intercepts, satellite photos and social media postings by separatists, some of which have been authenticated by U.S. experts.

The intelligence officials were cautious in their assessment, noting that while the Russians have been arming separatists in eastern Ukraine, the U.S. had no direct evidence that the missile used to shoot down the passenger jet came from Russia.

Meanwhile, Ukraine's Defense Ministry announced that two Ukrainian military fighter jets were shot down Wednesday in the eastern part of the country, over an area called Savur Mogila.

Defense Ministry spokesman Oleksiy Dmitrashkovsky told The Associated Press that the planes may have been carrying up to two crew members each.

Fox News' Catherine Herridge and The Associated Press contributed to this report.