WASHINGTON — Malaysia’s prime minister on Thursday condemned murder charges that earlier this week were brought against Russian and Ukrainian nationals as part of an international investigation into the 2014 crash of Malaysia Airlines Flight 17.

Mahathir Mohamad said the charges are politically motivated. “As far as we are concerned we want proof of guilt,” he said. “But so far, there is no proof. Only hearsay.”

“We are very unhappy because from the very beginning, it became a political issue on how to accuse Russia of the wrongdoing,” he told reporters. “Even before they examine (the debris), they already say Russia. So it is very difficult for us to accept that.”

Mahathir has a history of anti-West sentiment. In a 2003 address to the United Malays National Organisation, he accused the European race of warmongering, saying European want “to control the world again.”

The Joint Investigation Team, or JIT, is made up of officials from the Dutch Public Prosecution Service and the country’s police, as well as with police and criminal justice officials from Australia, Belgium, Malaysia and Ukraine.

Malaysia’s Foreign Ministry said the country would remain committed to ensuring the investigation’s transparency, credibility and effectiveness, and it urged all parties to cooperate.

The JIT on Wednesday charged three Russians and one Ukrainian with murder. MH17 from Amsterdam to Kuala Lumpur was brought down on July 17, 2014, over eastern Ukraine by what investigators said was a Buk missile from a Russian anti-aircraft unit. Investigators believe the Ukrainian rebels probably mistook the Boeing 777 passenger jet for a Ukrainian military plane.

At the time of the crash, the region was mired in a conflict between the Ukrainian government and pro-Russia separatists.

“We have taken into account the armed conflict," said Fred Westerbeke, the chief public prosecutor. "The possibility exists that the suspects wanted to shoot a military plane instead of a passenger flight. Even if that was the original plan, we do hold them responsible for downing MH17.”

Russian officials have disputed the findings of the JIT throughout the process.

"Russia had no opportunity to take part in it, although from the very beginning, from the first days after this tragedy, she took the initiative, tried to become part of this investigation of this monstrous disaster," Russian presidential spokesperson Dmitry Peskov told Russia's Tass news agency. "Therefore, our attitude to this investigation is very well known."

Although a trial is set for March in the Netherlands, it is unlikely the defendants will ever stand trial. Russia has previously denied extradition requests, and both Russia and Ukraine forbid the extradition of their citizens.

The three Russians charged are Igor Girkin, a retired colonel in Russia’s main intelligence agency, FSB; Sergey Dubinskiy, identified as a former employee of Russia’s GRU military intelligence agency; and Oleg Pulatov, identified as a former soldier in military intelligence. Investigators also charged Leonid Kharchenko, a Ukrainian citizen who led a combat unit in the Donetsk region.

Girkin led Russian and separatist forces in Ukraine’s Donetsk region in 2014. He dismissed the accusations in a telephone interview with The Associated Press, saying the “insurgents did not shoot down the Boeing.”

Eileen Ng with The Associated Press contributed to this report.