Malaysian Prime Minister Najib Razak said on Saturday he would meet his Dutch counterpart Mark Rutte next week to discuss how to secure full access for investigators to the site in Ukraine where a Malaysian airliner was downed.
Pro-Russian separatists remain in control of the area in eastern Ukraine where the Malaysia Airlines Boeing 777 was brought down last week on a flight from Amsterdam to Kuala Lumpur, killing all 298 on board.
Najib helped clinch a deal with separatist leaders to secure the return of the victims' remains as well as the aircraft's two "black boxes", critical to determining what happened to the flight. It was now time, he said, to proceed with the full investigation.
"My priority now is to ensure the third part of the deal is honoured, and that international investigators are given full and secure access to the site," he said in a statement.
"This will require the cooperation of those in control of the crash site and the Ukrainian armed forces."
The statement said Najib would fly to the Netherlands for talks on Wednesday, after Malaysia has marked the end of the Muslim fasting month of Ramadan.
Difficult situation on ground
Malaysian experts believe at least 30 investigators will be required to cover the full site of the crash, the statement said, in addition to Dutch investigators and an expert from the United Nations' civil aviation body, the ICAO.
"Unfortunately events on the ground - including ongoing fighting between Ukrainian and separatist forces - prevent such a large contingent of investigators being deployed," it said.
Ukraine's armed forces have been trying to dislodge separatists from towns in eastern Ukraine since April.
The United States and other Western countries suggest the separatists downed the plane with a surface-to-air missile supplied by Russia. The separatists deny shooting down the plane and Russia says it has provided no such weapons.
A total of 193 Dutch nationals and 43 Malaysians were among the victims aboard MH-17.
The Dutch Safety Board said this week it had taken control of an investigation into the crash and would coordinate a team of investigators from Ukraine, Malaysia, Germany, the United States, Britain, Russia and the ICAO.
The European Union reached an outline agreement on Friday to impose the first economic sanctions on Russia over its annexation of Ukraine's Crimea peninsula in March and suspicions that it is actively involved in destablising eastern Ukraine.
The 28-nation EU also imposed travel bans and asset freezes on Russian intelligence chiefs and other officials accused of undermining Ukraine's sovereignty.
One official added to the list, Alexander Tkachyov, the governor of Russia's southern Krasnodar region, said he had no regrets about any action he had taken. He said the West was "settling scores" for the success of the Winter Olympics at Sochi in his region in February.
"I have no regrets because of the sanctions," Tkachyov said on Twitter. "Even if I had known about this beforehand, I would do what I did."