International prosecutors investigating the downing of flight MH17 over eastern Ukraine in 2014 say the Buk missile that hit the plane was from Russia.

They also narrowed down the area it was fired from to a field in territory controlled by Russian-backed rebels.

All 298 people on board the Boeing 777 died when it broke apart in mid-air flying from Amsterdam to Kuala Lumpur.

Russia says the conclusions are "extremely political" and its Buk missiles "never shot down" the plane.

"Based on the criminal investigation, we have concluded that flight MH17 was downed by a Buk missile of the series 9M83 that came from the territory of the Russian Federation," chief Dutch police investigator Wilbert Paulissen said in a news conference on Thursday.

The missile launcher was later taken back to Russia, he said.

An inquiry by the Dutch Safety Board last year found that a Russian-made Buk missile hit the plane but did not say where it was fired from.

But Russia has rejected the conclusions, calling them "extremely political".

"This is of course a provocative statement... it has nothing to do with investigating the tragedy that took away the lives of so many people," said Leonid Slutsky, the head of the parliamentary committee for the CIS (Commonwealth of Independent State).

"These conclusions seek to achieve only one objective - to further marginalise the image of Russia in the global political and information space," he added.

Who gave the order?

Prosecutors have narrowed the missile launch site down to a specific field near the village of Pervomaiskyi, which was then in rebel hands.

They established the identities of about 100 people "linked to the crash or the transport of the Buk" missile, but they are yet to determine who could be held criminally responsible.

There is a need to establish who gave the order to move the missile launcher into eastern Ukraine, and where the order for it to be fired came from, investigators said.

The Dutch-led Joint Investigation Team (JIT) consists of prosecutors from the Netherlands, Australia, Belgium, Malaysia and Ukraine.

Many witnesses

Prosecutors played recordings from intercepted phone calls during their news conference.

They said witnesses reported seeing the missile launcher move from Russia into Ukraine and presented pictures and videos.

The launch site was pinpointed by "many witnesses", prosecutors said.

Relatives were briefed before the JIT released their preliminary findings.

"They told us how the Buk was transported [and] how they came to that evidence from phone taps, photo, film material, video," Robby Oehler, whose niece was killed in the crash, told the BBC.

Separatist rebels have denied they were involved.

"We never had such air defence systems, nor the people who could operate them," Eduard Basurin, military deputy operational commander at the rebel Donetsk People's Republic, told the Interfax news agency.

"Therefore we could not have shot down the Boeing [flight MH17]."

Earlier this week, Russia said it had radar data showing that the missile was not fired from rebel-held territory.

The JIT does not yet have access to that data, prosecutors said.

Russia's changing story

In the two years since MH17 was shot down, Russian officials have presented several theories about what happened.

21 July 2014: Four days after the tragedy, Russia's defence ministry presented satellite photos and other images suggesting it was downed by a Ukrainian surface-to-air Buk missile or a Ukrainian military jet

June 2015: Russia's Investigations Committee named a "key witness" - a Ukrainian "aircraft ordnance technician" - who claimed that the Boeing was downed by a Ukrainian Su-25 fighter

October 2015: Buk missile producer Almaz-Antey said that the plane was indeed downed by a Buk, but an old one - which Russia no longer had in its arsenal

September 2016: Russia's defence ministry released what it said were radar data suggesting MH17 was shot down by a missile, but not one fired by Russian-backed rebels