Russia says it has launched an investigation into Wednesday's crash of a Russian military plane, saying it was shot down in a "terrorist act" by Ukraine. Ukraine is calling for an international probe.

Russia's defense ministry said on Wednesday the transport plane crashed in the country's Belgorod region, near the Ukrainian border.

The ministry said the plane was attacked by an anti-aircraft missile from the territory of Ukraine. It said all people on board died, and that the plane was carrying 65 Ukrainian prisoners of war.

The ministry also said on Thursday that its air defense shot down rocket shells launched from Ukraine over the Belgorod region.

Russia's Investigative Committee announced on Thursday that it opened a full investigation into the crash.

The committee said it is examining the flight data recorder and other equipment recovered at the crash site. The committee added it is trying to identify members of Ukraine's armed forces who were involved in the terrorist act.

Ukraine has yet to mention whether it was involved in the crash. It says its security service is investigating the incident.

The defense ministry's intelligence agency says it is uncertain whether the plane was carrying Ukrainian prisoners of war.

Ukraine is seeking an international investigation into the crash.