Filip Warwick, Jabeen Bhatti and Gregg Zoroya

USA TODAY

Corrections & Clarifications: A previous version misidentified the Malaysian Minister of Transport, Liow Tiong Lai

HRABOVE, Ukraine — Just days after Malaysia Airlines Flight 17 was apparently shot down here by a missile, the prospect of a thorough crash-scene investigation faded Sunday as most of the 298 human remains were seized and whisked away by separatists, and international accident investigators had yet to arrive.

"Malaysia is very concerned that the sanctity of the crash site has been severely compromised," Malaysian Minister of Transport Datuk Seri Liow Tiong Lai said in a statement from Ukraine, where he has led a team of 133 investigators from his country.

Dutch anger was mounting as well. "I am shocked by the images of utterly disrespectful behavior at the crash site," Dutch Prime Minister Mark Rutte said. "This is utterly disgusting."

Armed rebels forced emergency workers -- including hundreds of miners who volunteered -- to hand over the remains. The bodies of at least 196 victims were loaded onto refrigerator rail cars and were headed for a rebel-held city, according to reports Sunday.

Liow Tiong Lai demanded that all human remains be allowed to be recovered, identified and repatriated. He insisted that flight data recorders — reportedly seized by separatists — not be tampered with.

"Malaysia demands immediate and unrestricted access to the crash site and guaranteed safety," said Liow Tiong Lai, who met with Ukrainian officials Sunday and whose team includes experts in forensics as well as search and recovery.

Rebel leader Alexander Borodai said the separatists have recovered the black boxes from Flight 17 and will hand them over to the International Civil Aviation Organization.

U.S. Secretary of State John Kerry said Sunday there was mounting evidence that a Russian-made missile, an SA-11, brought down the airliner. Appearing on CNN's State of the Union, he said that a U.S. tracking analysis detected the launch of a surface-to-air missile Thursday with a trajectory that "went through the plane."

"It obviously points a clear finger at the separatists," he said.

The U.S. Embassy in Kiev issued a statement saying the tracked launch originated from separatist-controlled territory in southeastern Ukraine and appeared to be an SA-11.

The latest U.S. intelligence assessment suggests more than one missile system was provided to the separatists by the Russians in the past week or so, a U.S. official said Saturday, according to reports by the Associated Press and The Wall Street Journal.

While there is not 100% certainty, the official told AP, "more and more there is the general belief that the systems were provided by the Russians."

The official said it's not entirely clear if the separatists just received the missile systems or if they had them for a short time and only in recent days were trained or able to operate them. The official was not authorized to discuss the matter publicly and spoke on condition of anonymity.

A group from the Organization for Security and Cooperation in Europe (OSCE) was at the crash site Sunday, and spokesman Michael Bociurkiw, described where the plane's engines and a large portion of the fuselage fell and burned. The air was thick with the stench of aviation fuel, and surrounding fields were burned over.

"Our monitors did observe body parts still laying in the open,'' Bociurkiw said. "We noticed that some personal belongings from the passengers had been collected and moved."

"At the cockpit area of the crash there were reportedly 37 bodies found including possible the cockpit crew," Bociurkiw said.

Russian news reports have said the bodies were being taken to Donetsk, a rebel-held stronghold.

The Netherlands lost 193 citizens in the crash, more than any other nation, and Dutch Prime Minister Mark Butte said Sunday that investigators from his country tasked with identifying the remains would reach the wreckage area by Monday, according to a Reuters report.

This weekend, just days after Thursday's crash of the airliner, which was en route from Amsterdam to Kuala Lumpur with 283 passengers and 15 crewmembers, personal belongings and pieces of the plane remained strewn across the fields in this remote eastern region close to the Russian border.

Hundreds of miners assisting with recovery walked the field in grid fashion in what appeared to be an organized effort to secure and recover remains and effects of crash victims and evidence that might explain what caused the crash.

At the scene, reporters were able to access a third and separate part of the crash site in the middle of a sunflower field where the cockpit lay. Local residents said it was this part of the scene immediately after the crash and the day after that separatist militiamen and police swarmed to secure and cordon off.

"The area around the cockpit crash was closed (Friday) — they were not allowing journalists in," said local resident Yelena Grigorievna, standing at the cockpit crash site Saturday.

"There was a large refrigerated lorry just by the road, and they were taking the bodies there in bags," she said. "On Friday, there were a few dead children here. Where they took them, I don't know."

Monitors from the OSCE inspected three refrigerated rail cars into which body bags containing the remains of 192 passengers had been placed. Bociurkiw said the smell was overwhelming.

Bociurkiw said the Soviet-era refrigerator cars appeared to be kept securely locked and received power from a nearby locomotive engine.

He said that the European monitors were, for the first time, escorted by heavily armed guards as they inspected the rail cars and the crash site.

"We had to access by foot, but again, we did see a larger area," he said. "We did notice when we arrived that there was a cordon of armed security personnel of both sides of the roadway. Some of them (were) masked and armed. We didn't feel any harassment this time as we did (Friday), but it was somewhat an intimidating environment, nonetheless."

He said that "one of the individuals who was seemingly leading the recovery operation" described a process of taking photos and video of each body before placing it in a bag and carrying remains to the side of the road.

"There seems to be a lack of leadership structure" at the crash site, he said.

Bociurkiw said his European monitors do not have aircraft investigation expertise. Those efforts are being undertaken by the large Malaysian team that arrived Saturday, as well as an international team comprised of officials from the Netherlands, Britain and the U.S. National Transportation and Safety Board that is being assembled.

Malaysian Minister Liow Tiong Lai said that the Ukrainian government "has been unable to establish a safe corridor to the crash site for the international team."

He said the efforts are further complicated by reports that there are competing separatist groups in the area of the crash "with no clear leader or chain of command."

Bhatti reported from Berlin, Warwick from Ukraine and Zoroya from McLean, Va. Contributing: Doug Stanglin in McLean, Calum MacLeod from Beijing, Oren Dorell from Washington, D.C., William M. Welch in Los Angeles; The Associated Press