Investigators earlier said that body fragments, found within 500 meters from the crash site, were almost impossible to identify and DNA tests are required.
"Samples will be taken from all relatives, the first batch is to be send to Moscow today," Alexander Neradko said.
Russia's prosecutor general said earlier Monday that he was taking personal charge of the investigation.
"This is due to the large number of casualties and the resonance of the investigation with the public," Yury Chaika told journalists.
The Boeing-737-500, owned by flagship Russian carrier Aeroflot, crashed on a railroad track linking Yekaterinburg and Perm, killing all 88 people onboard. Technical failure is seen as the most likely cause of the crash.
Two experts from Boeing will help determine the cause of the crash, the U.S. company's representative in Moscow said Monday.
"Two of our technical experts have flown to the site of the tragedy to assist in the investigation," Boeing spokesman Dmitry Khrol said.