The Malaysian premier said he had received assurances from the prime minister of the self-proclaimed Donetsk People's Republic, Alexander Borodai, that the remains of 282 people will be moved by train to the Ukrainian city of Kharkiv and handed over.
He also added that the two black boxes will be given to a Malaysian team, and that independent international investigators would "be guaranteed safe access" to the crash site to begin their probe.
Najib said in a televised press statement that Malaysia had been working "behind the scenes to establish contact with those in charge of the MH17 crash site".
"That contact has now been made... Tonight, we have established the basis of an agreement," Najib said, adding that he had earlier spoken to Borodai.
The Malaysia Airlines flight crashed last Thursday over strife-torn eastern Ukraine with 298 people aboard en route from Amsterdam to Kuala Lumpur.
It is believed to have been shot down by a missile. Access to the site in the violence-wracked area has so far been hampered by armed separatists who control the region.
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ