Artillery boomed in the distance as the 70-member team of Dutch and Australian experts painstakingly combed a patch of scrubland not far from the site of bloody clashes between Ukrainian soldiers and pro-Russian separatist rebels.
The team's top priority: collecting the remains of as many as 80 victims that have been lying out in the open, baking in the midsummer heat, for more than two weeks because investigators were prevented by the fighting from reaching the scene.
Pieter-Jaap Aalbersberg, head of the Dutch recovery mission, said in the Ukrainian capital of Kiev that the experts were able to gather some of the human remains. He would not give details out of respect for the victims' relatives.
The pace set Friday hinted at the magnitude of the task ahead.
Aalbersberg said a team of 30 experts spent two hours after lunchtime searching an area of just 30 square yards (25 square meters). The overall area to explore covers more than 8 square miles (20 square kilometers).
"If we have maximum capacity, we think we need at least three weeks to do a full search, but that's a very thin prospect," he said.
The objects collected included papers and books belonging to some of the 298 people killed aboard the Boeing 777 that was shot down on July 17 with what the West says was a Russian-made missile fired by the rebels.
In a haphazard effort overseen by the rebels, more than 200 bodies were collected by rescue workers and were turned over to Dutch authorities last week for examination and identification.
Everything discovered Friday was first identified and photographed, then put into bags by recovery workers wearing protective gear. The bags were then placed in the blue buckets.
Some recovery experts photographed pieces of the plane's fuselage and tail. Rebel fighters guarded the perimeter of the zone and kept their distance from the investigators.
The remains will be put in refrigerated train cars Saturday, taken 190 miles (300 kilometers) to the city of Kharkiv and then flown to the Netherlands. Nearly 200 of the victims were Dutch.
"Perseverance pays off," Dutch Prime Minister Mark Rutte said. "The first step has been taken, but the security situation is still volatile."
Several hours before the team arrived at the crash site outside the village of Hrabove, at least 10 Ukrainian soldiers were killed when their convoy was ambushed by rebels in a town 12 miles (20 kilometers) to the south.
Thirteen more soldiers were unaccounted for after the attack, officials said, and the bodies of four other people were being examined to determine whether they were soldiers or rebels.
The investigators plus officials with the Organization for Security and Cooperation in Europe traveled to the crash site from the rebel-held city of Donetsk in 15 cars and a bus.
The three-hour journey took the investigating team through the government-held town of Debaltseve and back into the separatist-controlled territory where the wreckage lies. At Debaltseve, the convoy was joined by Red Cross vehicles.
As the experts began working, artillery fire could be heard in the distance. It was unclear how far away the shells were landing and which side was firing.
Aalbersberg said investigators will face an easier journey to the site now they are relocating from Donetsk to a base on the grounds of a school, clinic and sports complex in the government-controlled town of Soledar, 90 kilometers (56 miles) from the scene.
Leonard reported from Kiev, Ukraine. Associated Press reporters Yuras Karmanau in Donetsk, Ukraine, and Toby Sterling in Amsterdam contributed to this report.