The Russian Investigative Committee said it shared its files on the crash of Malaysian Airlines flight MH17 with Dutch investigators visiting Moscow, but the Dutch team declined to reciprocate.
Committee spokesman Vladimir Markin said committee staff met with representatives of the Dutch national prosecution service on July 6 to discuss their separate inquiries into the Boeing 777's downing over eastern Ukraine two years ago.
Markin said the committee expressed its readiness to cooperate with the Dutch inquiry and provided files from its own investigation of the crash.
But while the Dutch accepted the data Russia provided, he said they declined to take any further assistance and also did not offer to share any data they have gathered.
The Dutch investigators have determined that the plane was shot down by a Russian-made Buk missile, which Ukraine and the West say was fired by Russia-backed separatists but Russia contends that it could have been fired by Ukrainian forces.
Markin said that "a bilateral exchange of information would significantly speed up the inquiry," but added that the Dutch have ignored Russian requests for assistance.
The Dutch team left Moscow on July 6 without commenting on its inquiry.