KHARKIV, Ukraine — An international push to secure the crash site of a Malaysian passenger jet shot down by a missile over eastern Ukraine stalled on Saturday, with the leader of a Dutch forensic mission announcing that scores of foreign police officers and experts gathered at a luxury hotel here would not start moving toward the site for at least five days.

Jan Tuinder, the head of a Dutch mission comprising 40 unarmed military police officers and around 20 forensic specialists, said the delay was needed to give the Ukrainian Parliament time to vote on Thursday to provide a “legal basis” for the deployment of foreign police officers on Ukrainian territory.

Efforts to reach the crash site had previously been hindered by heavily armed pro-Russia rebels, who control the area, but now another obstacle appears to be Ukraine, whose military has been gaining ground against the rebels and is wary of halting its offensive.

The jet, a Malaysia Airlines Boeing 777, crashed in territory in eastern Ukraine held by pro-Russia rebels on July 17, and while most of the bodies of the 298 victims of Flight 17 have now been recovered and flown to the Netherlands for identification, forensic investigators have not been able to reach the area in sufficient numbers to ensure that all the bodies have been found and collect debris that could provide evidence of who brought the plane down. The Netherlands, whose citizens accounted for around two-thirds of the crash victims, is leading an international effort to get to the bottom of what happened to Flight 17.