An Azerbaijani airliner has crashed in Kazakhstan after being diverted, killing 38 of 67 people on board. Some experts alleged that the plane went down after being hit by Russian air defense systems. Some things to know about the crash and the speculation about a possible cause:

Even as a probe was starting of the crash of an Azerbaijan Airlines airliner in Kazakhstan, speculation was mounting about why the plane went down.

Russian aviation authorities said the Azerbaijan Airlines plane had hit a flock of birds. But some experts cast doubt on that account, pointing to footage showing apparent holes in the fuselage.

Kazakh authorities have recovered the flight data recorder and an investigation is under way. Shortly after the crash, reports from Russian state-controlled TV said the most likely cause was a strike from a flock of birds.

At least thirty-eight people were killed after an Azerbaijan Airlines plane bound for Russia crashed in Kazakhstan on Christmas morning, a Kazakh official said, adding that 29 others, including two children, survived the disaster. Investigators continue to work to determine what caused the crash.

HAUNTING footage shows passengers on board the doomed Azerbaijan Airlines flight just moments before it crashed – killing 38 people. Dozens of passengers, including children, miraculously

An Azerbaijan Airlines passenger aircraft crashed near Kazakhstan's Aktau Airport close to the Caspian Sea on Wednesday morning.

Russia’s state aviation authority said the Azerbaijan Airlines plane had been trying to make an emergency landing. The Kazakh authorities said that at least 29 people survived.

Ukraine has claimed to have struck a Russian industrial facility producing fuel for missiles, as Moscow says it has foiled several assassination plots on senior officers.Kyiv said on Thursday that its air force had had carried out a strike in Russia’s Rostov region on a factory which was used to produce solid fuel for ballistic missiles used in attacks on Ukraine.

Questions were being asked Thursday about the cause of an airliner crash in Kazakhstan the day before, as Azerbaijan held a day of mourning for the dozens of victims of

A U.S. official tells NBC News there are early indications that the passenger plane that crashed in Kazakhstan may have been hit by a Russian anti-aircraft system. The official said if it turns out to be the case,