Prosecutors have sought to put pressure on Russia to provide information about the downing of Malaysia Airlines Flight MH17 over eastern Ukraine in July 2014.
They said they wanted information about the Buk missile that shot down the airliner, killing 298 people on board.
The criminal inquiry was at “a very advanced stage”, they said, and results would be presented after the summer.
The West and Ukraine say Russian-backed rebels were responsible but Russia accuses Ukrainian forces.
In a statement, the Dutch-led prosecutors said they had made “several requests” for assistance – but were still waiting for information from Moscow.
They said a few issues, including forensic tests, were taking more time than expected.
However, the first conclusions regarding the type of the weapon used and the exact launch site are expected to be published in autumn.
Flight MH17 from Amsterdam to Kuala Lumpur crashed at the height of the conflict between Ukrainian government troops and pro-Russian separatists.
Last year, a Dutch report concluded it was downed by a Russian-made Buk missile, but did not say who fired it.
Some families of the victims are suing Russia and its President Vladimir Putin in the European Court of Human Rights.
Their claim is based on the violation of a passenger’s right to life, News.com.au reported earlier this month.
They are seeking A$10 million Australian dollars ($7.2m; £4.9m) for each victim, and the lawsuit names both the Russian state and its president as respondents.
A senator with Mr Putin’s party was quoted in state media as saying the claim was “legally nonsensical and has no chance”.
Separately, families of six Malaysia Airlines crew members who were killed filed a lawsuit on Thursday blaming the carrier for the tragedy.
They accuse the company of negligence and breach of contract.