At least 38 people were killed when a passenger jet headed for Russia crashed in Kazakhstan in an incident that Ukraine officials and aviation experts said was likely caused by Russian antiaircraft fire.

The Azerbaijan Airlines plane was flying from Baku in Azerbaijan to Grozny in Russia and diverted course over an area where Moscow’s air defenses have battled Ukrainian drones in recent weeks. The flight—carrying 62 passengers and five crew members—crashed near Aktau in western Kazakhstan after turning around and flying east over the Caspian Sea. As many as 29 passengers survived.

Citing assessments of footage of the crash, the damage to the aircraft, and recent military activity, aviation-security firm, Osprey Flight Solutions, said in an alert to airlines that the flight “was likely shot down by a Russian military air-defense system.”

“Video of the wreckage and the circumstances around the airspace security environment in southwest Russia indicates the possibility the aircraft was hit by some form of antiaircraft fire,” said Matt Borie, chief intelligence officer at Osprey said in an interview.

A Ukrainian national security official, Andriy Kovalenko, said in an X post that the plane “was shot down by a Russian air-defense system,” citing visible damage to the plane.

“Russia should have closed the airspace over Grozny but failed to do so,” Kovalenko said. “The plane was damaged by the Russians and was sent to Kazakhstan instead of being urgently landed in Grozny to save lives.”

A drone view shows emergency specialists working at the crash site of an Azerbaijan Airlines passenger plane near the city of Aktau, Kazakhstan December 25, 2024. REUTERS/Azamat Sarsenbayev

Russian officials couldn’t be immediately reached for comments about the Osprey and Ukraine assessments.

Azerbaijan and Kazakhstan said they were cooperating on an investigation and cited different potential reasons for the crash.

Azerbaijan Airlines said the Embraer 190 passenger jet may have collided with a flock of birds. Azerbaijan’s president said that he was told the plane had been diverted due to poor weather conditions. He said an investigation into the incident was ongoing. Officials said the aircraft’s black box was recovered.

Footage posted from near the scene on Wednesday morning showed the aircraft engulfed in flames after it made an emergency landing in a field.

Twenty-five minutes before the plane was scheduled to land in Grozny, its crew alerted air-traffic controllers at Aktau airport that they needed to make an emergency landing there, the ministry said.

Half an hour later, shortly before noon local time, the plane crashed in a field about 2 miles from Aktau airport. Flight-tracking service Flightradar24 said heavy GPS spoofing in the area, which tampers with signals so a plane’s position can’t be tracked, could have complicated any diversion.

Some aviation experts have suggested that perforations in the plane’s tail section, visible in footage of the crash site posted by Kazakhstan’s Emergencies Ministry and verified by Storyful—owned by News Corp, the parent company of The Wall Street Journal—looked consistent with a possible missile attack or the work of air defenses.

Borie said the damage pattern available in footage of the incident doesn’t seem to match that of a bird strike, but cautioned that further information and input from regulators were needed to confirm the possibility.

Footage posted on social media and verified by Storyful showed the two-engine jetliner descending at a dangerously steep angle before leveling out somewhat on its descent toward Aktau.

The plane’s undulating flight path—and a sudden downward turn at a dangerously steep angle ahead of landing—suggests the pilots were struggling to guide it, experts said.

“The plane seems to have had multiple control issues,” said Alexandre Avrane, founder of AeroTransport Data Bank, which tracks aircraft worldwide.

When it set off from Baku on Wednesday morning, the Azerbaijan Airlines plane was flying over a part of Russia’s North Caucasus that has been targeted by Ukrainian drones in recent weeks. Russia’s Defense Ministry said it had shot down 59 Ukrainian drones overnight into Wednesday, most of them in areas bordering Ukraine.

One of them was shot down over Vladikavkaz, west of Grozny, just three hours before the plane crashed on Wednesday, said the regional governor there, Sergei Menyaylo. On Dec. 15, a drone struck a campus of Russia’s National Guard in Grozny and at least two other drones were shot down by air defenses.

Ukrainian drone attacks across large parts of Russia have recently affected commercial flights, including temporarily halting operations at Kazan airport, about 500 miles east of Moscow, before the crash.

Osprey issued an alert warning airline customers of an increased risk as a result. On Wednesday, Azerbaijan Airlines said it had halted flights to Grozny and Makhachkala, according to TASS.

Russian authorities often use SA-22 antiaircraft systems to defend against those drones, which are equipped with surface-to-air missiles and 30mm cannon ammunition. The SA-22 has the range to strike an aircraft at cruise altitude.

Earlier this month, TASS posted footage from Russia’s Defense Ministry of an SA-22 system shooting down a Ukrainian drone over the Kursk region in southwest Russia.

Dan Michaels contributed to this article.

Write to Matthew Luxmoore at matthew.luxmoore@wsj.com and Benjamin Katz at ben.katz@wsj.com