KUALA LUMPUR, July 22  -- Malaysian Prime Minister Najib Razak said Tuesday that he welcomed the progress in the agreement Malaysia brokered with Ukrainian rebel leaders, and praised the Malaysian team for their work in securing the return of the remains of the victims, and taking custody of the black boxes.

"I am pleased to confirm that the first two conditions have now been met," which were the return of the remains of those who lost their lives and the handover of the black boxes, he said.

"The Malaysian team have taken custody of the black boxes, which appear to be in good condition. They will be held securely in Malaysian custody while the international investigation team is being formalized. At that time, we will pass the black boxes to the international investigation team for further analysis," Najib said.

He said so far the agreement had been honored.

"Malaysia requests that this cooperation continue, and that investigators are granted full access to the site which was agreed. "

"I would like to thank the Malaysian team on the ground, who have worked hard to support this operation. Thanks to their efforts, we are closer to finding out what happened to aircraft, and fulfilling our shared responsibility to those who lost their lives," he added.

Ukrainian rebels cleared the departure on Tuesday of a train loaded with remains of victims in crashed Malaysia Airlines MH 17 while handing over to Malaysian experts black boxes of the flight allegedly shot down in rebel-held eastern Ukraine.

Under an agreement between Malaysian Prime Minister Najib Razak and Ukrainian insurgents, international forensics experts were finally allowed to access the crash site Monday and collect the bodies.