“We are asking that the suspects Girkin, Dubinsky, Pulatov and Kharchenko, each for their responsibility of crashing a plane leading to the death and murder of 298 people, be sentenced to life in prison,” prosecutor Manon Ridderbeks told the court on Wednesday.

All four have refused to appear in court in the Netherlands and are being tried in absentia.

Prosecutors have argued this week that the four suspects played pivotal roles in securing the BUK system, which was most likely intended to strike a Ukrainian warplane.

International investigators say the missile was originally brought from a Russian military base, ostensibly to be used in the fight against Ukrainian forces.

MH17: Dutch prosecutors begin 3 days of closing arguments over fatal flight

“Our evidence is convincing and abundant. We have many sources where the evidence comes from and they support each other,” chief prosecutor Digna van Boetzelaer told Agence France-Presse.

Prosecutors said the missile’s deployment was planned and organised, and that it did not matter whether the suspects made a mistake in targeting a passenger plane.

“If we consider how much time the defendants put into planning and organising the deployment of the BUK, it is all the more poignant how little attention they appear to have given to the risk of inadvertently shooting down a passenger aircraft,” prosecutors argued, according to trial documents on Wednesday.

“In legal terms, the defendants were civilians and were therefore not allowed to shoot at any aircraft, whether civilian or military.”

Anton Kotte, who lost his son, daughter-in-law and grandson in the crash, welcomed Wednesday’s proceedings.

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Russian military blamed for downing MH17 with missile

Russian military blamed for downing MH17 with missile

“There were children from one year old on that plane. They had their whole life … there’s no life. It’s awful,” he told reporters outside the court.

Piet Ploeg, who lost three relatives in the crash, said the sentence request was called for.

“There’s only one sentence that’s appropriate for this crime, and that’s life imprisonment,” he told Agence France-Presse.

The hearings come as fresh tensions soar over Ukraine, with the West accusing Moscow of planning an invasion.

Kyiv has been battling a pro-Moscow insurgency in two breakaway regions bordering Russia since 2014, when the Kremlin annexed Ukraine’s Crimean peninsula.

Russia has recently massed troops near Ukraine’s borders and the West has for weeks accused it of planning an invasion, warning Moscow of massive sanctions should it launch an attack.

Russian Foreign Minister Sergei Lavrov accused the United States of “double standards” soon before the trial started.

He told television channel RT that Washington instructed US airlines not to fly over Russian territory near the Ukrainian border in the spring of 2014, but no one closed the airspace after war broke out later that year.

Western nations imposed tough sanctions on Russia amid international outrage over the shooting down of flight MH17.

The best known of the suspects, 49-year-old Girkin – nicknamed “gunner” – was one of the main separatist commanders at the start of the conflict with the Ukrainian army.

Investigators release calls linking MH17 suspects to Russian officials

He said on Wednesday he was not surprised by the prosecutors’ request, and denied the rebels shot down the plane.

“If they could have sentenced me to death, they would have done it, no doubt about it,” he was quoted as saying by Russia’s Interfax news agency.

Dubinsky, 57, is said to be linked to Russian military intelligence, while Pulatov, 53, is a former member of the Russian special forces and Dubinsky’s deputy.

Kharchenko, 48, is believed to have led a separatist unit in eastern Ukraine.

Pulatov denies any involvement in the crash, and his lawyers said on Wednesday the trial evidence was “incomplete”, calling for him to be acquitted, Dutch media reported.