A military plane said to be carrying senior Kazakh security officials has crashed in the south of the country, reports say, according to BBC News.

More than 20 people were on board the flight, which went down near the city of Shymkent, Kazakh TV said.

The Antonov An-72 plane was carrying high-ranking members of Kazakhstan's border service, Interfax-Kazakhstan news agency says.

An unconfirmed source told the agency all those on board had been killed.