KIEV, Ukraine (AP) — Emergency workers, police officers and even off-duty coal miners — dressed in overalls and covered in soot — searched Friday through wreckage and bodies scattered over a wide stretch of Ukrainian farmland after a Malaysian jetliner flying high above Ukraine's battlefield was shot down from the sky, killing 298 people.

Separatist rebels who control the area where the plane went down said they had recovered most of the plane's black boxes and were considering what to do with them. Their statement had profound implications for the integrity of the plane crash investigation.

Ukraine, whose investigators have no access to the area, has called for an international probe to determine who attacked the plane and insisted it was not its military. U.S. intelligence authorities said a surface-to-air missile downed the plane, but could not say who fired it.

For the first day in months, there was no sign of fighting in the area Friday, though there was no official word of a cease-fire either. But access remained difficult and dangerous. The road from Donetsk, the largest city in the region, to the crash site was marked by five rebel checkpoints Friday, with document checks at each.

The crash site was sprawling, spread out over fields between two villages in eastern Ukraine.  Large chunks of the Boeing 777 that bore the airline's red, white and blue markings lay strewn over one field.  The cockpit and one turbine lay a kilometer (a half-mile) apart, and residents said the tail landed another 10 kilometers (six miles) away, indicating the aircraft most likely broke up before hitting the ground.

Bodies and body parts were everywhere: in a sunflower field, even in the streets of the rebel-held village of Rozsypne, 40 kilometers (25 miles) from the Russian border. One rebel militiamen in the village told The Associated Press that he had seen a part of the fuselage, more evidence the plane was struck by a projectile.

The area has seen heavy fighting between government troops and pro-Russia separatists, and rebels had bragged about shooting down two Ukrainian military jets in the region just a day earlier.

Ukraine accused the rebels of shooting down the Malaysia Airways plane. The rebels denied it and accused government forces of the same; President Petro Poroshenko denied it as well.

Russian President Vladimir Putin blamed Ukraine for the downing, saying it was responsible for the unrest in its Russian-speaking eastern regions — but did not accuse Ukraine of shooting the plane down and not address the key question of whether Russia gave the rebels such a powerful missile. Ukraine and the West have accused Russia of supporting the rebels, a charge that Moscow denies.

Poroshenko called the attack an "act of terrorism" and demanded an international investigation.

An assistant to the insurgency's military commander, Igor Girkin, said Friday on condition of anonymity that eight out of the plane's 12 recording devices had been located at the crash site. He did not elaborate. Since airplanes normally have both a flight data recorder and a cockpit voice recorder, it was not exactly clear what devices he was referring to.

He said Girkin, was still considering whether to give international crash investigators access to the sprawling crash site. Any investigators would need specific permission from the rebel leadership before they could safely film or take photos at the crash site.

Kenneth Quinn of the Flight Safety Foundation said an international coalition of countries should lead the investigation. The Unites States has offered to help.

Malaysia's prime minister said there was no distress call before the plane went down and that the flight route was declared safe by the International Civil Aviation Organization.

Aviation authorities in several countries, including the FAA in the United States, had issued warnings not to fly over parts of Ukraine prior to Thursday's crash, but many carriers, including cash-strapped Malaysia Airlines, had continued to use the route because "it is a shorter route, which means less fuel and therefore less money," said aviation expert Norman Shanks.

Within hours of the crash, several airlines announced they were avoiding parts of Ukrainian airspace.

On Friday, Ukraine's state aviation service closed the airspace over two regions currently gripped by fighting — Donetsk and Luhansk — and Russian aviation regulators said Russian airlines have suspended all transit flights over Ukraine.

At a news conference in Kuala Lumpur, Malaysia Airlines updated its nationality count of passengers, saying the plane carried 173 Dutch, 24 Malaysian, 27 Australian, 12 Indonesian, 9 British, 4 German, 4 Belgian, 3 Filipino and one person each from Canada and New Zealand.

Passengers on the plane included a large contingent of world-renowned AIDS researchers and activists headed to an international AIDS conference in Melbourne, Australia. News of their deaths sparked an outpouring of grief across the global scientific community.

In Kuala Lumpur, several relatives of victims were meeting with counselors at the international airport. A distraught Akmar Mohamad Noor, 67, said her older sister was coming to visit the family for the first time in five years.

"She called me just before she boarded the plane and said, 'See you soon,'" Akmar said.

In the Netherlands, flags were flying at half-staff across the country as residents mourned the victims.

Anton Gerashenko, an adviser to Ukraine's interior minister, said on his Facebook page the plane was flying at about 10,000 meters (33,000 feet) when it was hit by a missile from a Buk launcher, which can fire up to an altitude of 22,000 meters (72,000 feet). He said only that his information was based on "intelligence."

Ukraine's security services produced what they said were two intercepted telephone conversations that showed rebels were responsible. In the first call, the security services said, rebel commander Igor Bezler tells a Russian military intelligence officer that rebel forces shot down a plane. In the second, two rebel fighters — one at the crash scene — say the rocket attack was carried out by insurgents about 25 kilometers (15 miles) north of the site.

Neither recording could be independently verified.

Russia's Interfax news agency quoted Donetsk rebel spokesman Sergey Kavtaradze as denying that the intercepted phone conversations were genuine.

President Barack Obama called the crash a "terrible tragedy" and spoke by phone with Putin as well as Poroshenko. Britain asked for an emergency meeting of the U.N. Security Council on Ukraine.

Putin said Ukraine bore responsibility for the crash.

"This tragedy would not have happened if there were peace on this land, if the military actions had not been renewed in southeast Ukraine," Putin said, according to a Kremlin statement Friday. "And, certainly, the state over whose territory this occurred bears responsibility for this awful tragedy."

At the United Nations, Ukrainian Ambassador Yuriy Sergeyev told the AP that Russia gave the separatists a sophisticated missile system and thus Moscow bears responsibility, along with the rebels.

A U.S. official said American intelligence authorities believe the plane was brought down by a surface-to-air missile but were still working to determine additional details about the crash.

But American intelligence assessments suggest it is more likely pro-Russian separatists or the Russians rather than Ukrainian government forces shot down the plane, according to the official, who spoke on condition of anonymity because he was not authorized to discuss the matter publicly.

Igor Sutyagin, a research fellow in Russian studies at the Royal United Services Institute, said both Ukrainian and Russian forces have SA-17 missile systems — also known as Buk ground-to-air launcher systems.

Poroshenko, the Ukrainian president, said his country's armed forces didn't shoot at any airborne targets.

Rebels had bragged recently about having acquired Buk systems. Before the crash Thursday, AP journalists saw a launcher that looked like a Buk missile system near the rebel-held eastern town of Snizhne.

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Karamau reported from Kiev. Others who contributed included Mstyslav Chernov in Rozsypne, Ukraine; Nataliya Vasilyeva in Moscow; Lolita C. Baldor and Darlene Superville in Washington; Mike Corder in The Hague, Netherlands; and Eileen Ng and Satish Cheney in Kuala Lumpur, Malaysia.