Four men accused of murder over the downing of Malaysia Airlines flight MH17 in 2014 went on trial in the Netherlands on Monday, with families of the 298 victims calling for justice.

The suspects -- three Russians and a Ukrainian -- were not present in the dock, but judges were expected to rule that the hearing could continue in their absence. Families have fought for more than half a decade for justice for the victims who were killed when the jet was shot down over eastern Ukraine by a Russian-made missile as it travelled from Amsterdam to Kuala Lumpur.

Head judge Hendrik Steenhuis declared the trial open at the court near Amsterdam's Schiphol Airport where the flight took off, adding that there had been a "tragic loss of human lives from all around the world" in the "atrocious disaster".

The courtroom in the high-security building was packed with relatives, lawyers and journalists, with many family members expected to speak during the trial. "I think today is of the highest importance," said Piet Ploeg, head of a foundation for MH17 victims who lost his brother, sister-in-law and nephew on the doomed flight.

"This is the first day that we will know what happened, who was responsible, why the plane was shot down, and to questions like what was Russia's role. There are relatives who want the smallest details, who want justice to be done. And there are others who want life to move on, who want to leave that all behind them."

'Gaps in evidence'

Dutch prosecutors last year charged Russian nationals Igor Girkin, Sergei Dubinsky, Oleg Pulatov and Ukrainian citizen Leonid Kharchenko -- all linked to pro-Moscow separatists in eastern Ukraine -- over the tragedy.

Despite international warrants issued for their arrest, none of the four suspects is expected to attend the court. Russia has long denied any involvement in the downing of MH17, and has offered a series of alternative explanations for the plane's downing. Moscow again on Friday accused the Netherlands of a "crude attempt to put pressure on the court".

"In the last days before the hearings everything was done to fill the gaps in the evidence presented and to camouflage the falsification of the facts of this version in advance," Russian foreign ministry spokeswoman Maria Zakharova said.

But Dutch Prime Minister Mark Rutte said on Friday that the trial was being held in "full independence" and was a "very important step to get to the truth and to find justice for the victims and their relatives". More than two-thirds of the victims -- 196 in total -- were Dutch.

US Secretary of State Mike Pompeo lent his support on the eve of the trial, saying he had "full confidence" in the Dutch justice system and those responsible "must be held accountable".

Dogged investigation

Prosecutors say the four men on trial were all linked to pro-Russian separatists on whose territory the plane's wreckage fell and who were instrumental in bringing the BUK missile system to Ukraine -- even if they did not pull the trigger.

Girkin, 49, also known by his pseudonym "Strelkov", is the most high-profile suspect -- a former Russian spy and historical re-enactment fan who helped kickstart the war in Ukraine. Dubinsky, 57, who has also been tied to Russian intelligence, allegedly served as the separatists' military intelligence chief and was allegedly responsible for requesting the delivery of the missile.

Pulatov, 53, was an ex-Russian special forces soldier and one of Dubinsky's deputies who allegedly helped transport the missile system to Ukraine, while Kharchenko, 48, allegedly led a separatist unit in eastern Ukraine and secured the missile launcher.

If found guilty, they could be handed life sentences. The charges against the four men resulted from a dogged international investigation led by Dutch authorities with the assistance of Australia, Belgium, Malaysia and Ukraine. Investigators say the BUK anti-aircraft missile was fired from rebel territory and was supplied by Russia, while the Netherlands and Australia have said they hold Moscow responsible.