KIEV, Ukraine — An adviser to Ukraine’s interior minister said a Malaysian passenger plane carrying 295 people has been shot down over a town in the east of the country.

Anton Gerashenko said on his Facebook page the plane was flying at an altitude of 10,000 meters (33,000 feet) when it was hit Thursday by a missile fired from a Buk launcher.

Malaysia Airlines said on its Twitter feed that it “has lost contact of MH17 from Amsterdam.”

A social media post attributed to a top Ukrainian rebel commander said the insurgents had shot down an army transporter at the location where the Malaysia Airlines plane crashed near the Russian border.

The comments by the top military commander of the self-proclaimed “Donetsk People’s Republic” suggest the separatists had shot down the Malaysia Airlines plane by mistake, believing it was a large Ukrainian army transport plane.

“We just downed an An-26 near Torez. It is down near the Progress mine,” said the VK page attributed to Igor Strelkov, which is frequently quoted by Ukrainian media.

The Boeing passenger liner came down close to town of Shaktarsk in the rebellion-wracked region of Donetsk after disappearing from the radar, an unnamed security source told Interfax-Ukraine news agency.

Regional officials said the number of dead was “not yet known” but Russian news agency Itar-Tass cited an unnamed source at Ukraine’s aviation authority as saying there were no survivors.

Eyewitnesses quoted by Russian news agency RIA Novosti spoke of dozens of bodies at the crash site.

Malaysian Prime Minister Najib Razak said on his Twitter feed he was “shocked by reports that an MH plane crashed.”

“We are launching an immediate investigation,” he wrote.

The airliner was flying from Amsterdam to Kuala Lumpur when it went down, Russian and Ukrainian news agencies reported.

France urged airline companies on Thursday to avoid Ukraine’s airspace.

Frederic Cuvillier, the junior minister of transport, said in a statement that he had given instructions for “French airlines to avoid Ukraine’s airspace as long as the reasons behind this catastrophe are not known.”

A similar missile launcher was seen by Associated Press journalists near the eastern Ukrainian town of Snizhne earlier Thursday.

The Russian-made Buk surface-to-air missile system can hit aircraft at an altitude of up to around 25 kilometers.

On Wednesday evening, a Ukrainian fighter jet was shot down by an air-to-air missile from a Russian plane, Ukrainian authorities said Thursday, adding to what Kiev says is mounting evidence that Moscow is directly supporting the separatist insurgents in eastern Ukraine. Security Council spokesman Andrei Lysenko said the pilot of the Sukhoi-25 jet hit by the air-to-air missile was forced to bail after his jet was shot down.

Pro-Russia rebels, meanwhile, claimed responsibility for strikes Wednesday on two Ukrainian Sukhoi-25 jets. The Ukrainian Defense Ministry said the second jet was hit by a portable surface-to-air missile, but added the pilot was unscathed and managed to land his plane safely

Moscow denies Western charges that is supporting the separatists or sowing unrest in its neighbor. The Russian Defense Ministry couldn’t be reached for comment Thursday about the Ukrainian jet and Russia’s foreign ministry didn’t respond to multiple requests for comment.

Earlier this week, Ukraine said a military transport plane was shot down Monday by a missile fired from Russian territory.

The rebels are known to possess portable anti-aircraft rocket launchers, but Ukrainian officials say that kind of weapon would have been unable to reach Monday’s plane at the altitude at which it was flying Monday. Aviation experts, however, have questioned whether the stricken transport plane was flying at the altitude Ukrainian officials had claimed.