ROZSYPNE, Ukraine — World leaders called for an immediate cease-fire in eastern Ukraine on Friday and demanded speedy access for international investigators to the crash site of the Malaysia Airlines jetliner shot down over the country’s battlefields.

The strong words came amid the contrasting images of emergency workers and off-duty coal miners fanning out across picturesque sunflower fields searching for charred pieces of wreckage from the Boeing 777.

The attack Thursday afternoon killed 298 people from nearly a dozen nations — including vacationers, students and a large contingent of scientists heading to an AIDS conference in Australia.

President Barack Obama called for an immediate cease-fire between Ukrainian government forces and pro-Russia separatists. He also called for a credible investigation.

“The eyes of the world are on eastern Ukraine, and we are going to make sure that the truth is out,” Obama said at the White House.

U.S. intelligence authorities said a surface-to-air missile brought down Malaysia Airlines Flight 17 as it traveled from Amsterdam to Kuala Lumpur. U.S. Ambassador Samantha Power told the U.N. Security Council in New York on Friday the missile was likely fired from a rebel-held area near the Russian border. 

The Ukrainian government in Kiev, the separatist pro-Russia rebels they are fighting and the Russia government that Ukraine accuses of supporting the rebels all denied shooting the plane down. Moscow also denies backing the rebels.

After holding an emergency session, the U.N. Security Council called for “a full, thorough and independent international investigation” into the downing of the plane.

Russian President Vladimir Putin said both sides in the Ukrainian conflict should put down their weapons and hold peace talks. On Thursday, Putin blamed Ukraine for the crash, saying Kiev was responsible for the unrest in its Russian-speaking eastern regions. But he didn’t accuse Ukraine of shooting the plane down and didn’t address the key question of whether Russia gave the rebels such a powerful missile. 

The Ukrainian Interior Ministry released a video purporting to show a truck carrying the Buk missile launcher it said was used to fire on the plane with one of its four missiles apparently missing. The ministry said the footage was filmed by a police surveillance squad at dawn Friday as the truck was heading to the city of Krasnodon toward the Russian border.

There was no way to independently verify the video.

Ukraine’s state aviation service closed the airspace Friday over two border regions gripped by separatist fighting — Donetsk and Luhansk — and Russian airlines suspended all flights over Ukraine.

Access to the sprawling crash site remained difficult and dangerous. The road into it from Donetsk, the largest city in the region, was marked by five rebel checkpoints, with document checks at each.

A commission of around 30 people, mostly officials representing the Organization for Security and Cooperation in Europe, traveled to the crash site Friday afternoon in the first such visit there by an international delegation. 

“No black boxes have been found ... we hope that experts will track them down and create a picture of what has happened,” Donetsk separatist leader Aleksandr Borodai said.

Yet earlier Friday, an aide to the military leader of Borodai’s group said authorities had recovered eight out of 12 recording devices.  Since planes usually have two black boxes — one for recording flight data and the other for recording cockpit voices —  it was not clear what the aide was referring to. It was possible he was referring to a variety of computer systems.

The crash site was spread out over fields between two villages in eastern Ukraine — Rozsypne and Hrabove. In the distance, the thud of Grad missile launchers being fired could be heard Friday morning.

In the sunflower fields around Rozsypne, 40 kilometers (25 miles) from the Russian border, lines of men disappeared into thick, tall growth that reached over their heads. One fainted after finding a body. Another body was covered in a coat.

About 70 off-duty coal miners joined the search, their faces still sooty from work.

In Hrabove, several miles away, large numbers of sticks, some made from tree branches, were affixed with red or white rags to mark spots where body parts were found.

Andrei Purgin, a leader of the pro-Russian separatists, told The Associated Press that after consultations with international diplomats and a former Ukrainian president, a decision has been reached for bodies to be taken to the government-controlled Black Sea city of Mariupol. 

Smashed watches and mobile phones, charred boarding passes and passports were among the debris.  

Large chunks of the plane, which 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 the tail landed 10 kilometers (six miles) away.  One rebel militiaman in Rozsypne told the AP the plane’s fuselage showed signs of being 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 Wednesday in the region.

Russian Foreign Minister Sergey Lavrov dismissed Kiev’s accusations that Moscow could be behind the attack. 

“Regarding those claims from Kiev that we allegedly did it ourselves: I have not heard a truthful statement from Kiev for months,” he told the Rossiya 24 television channel. 

He also said Russia has no intention of getting its hands on the plane’s black boxes and added they should be given to international aviation organizations.

Ukrainian Prime Minister Arseniy Yatsenyuk described the attack as an “international crime” whose perpetrators should be punished in an international tribunal.

Malaysian Transport Minister Liow Tiong Lay insisted again Friday that the airline’s path was an internationally approved route and denied accusations the airline was trying to save fuel and money by taking a more direct flight path across Ukraine.

Aviation authorities in several countries, including the FAA in the United States, had issued previous warnings not to fly over parts of Ukraine after Russia annexed the Crimean Peninsula in March. Within hours of the crash Thursday, several airlines announced they were avoiding parts of Ukrainian airspace. 

 Peter Leonard reported from Kiev.  Others who contributed included Yuras Karmanau in Kiev; Julie Pace in Washington; Mstyslav Chernov in Rozsypne, Ukraine; Nataliya Vasilyeva and Laura Mills in Moscow; Mike Corder in The Hague, Netherlands; Edith M. Lederer at the United Nations; and Eileen Ng and Satish Cheney in Kuala Lumpur, Malaysia.