Twenty-one people were killed when an airliner crashed on Tuesday near the Kazakh city of Almaty, according to Kazakhstan’s Prosecutor General’s office.

The plane, a Bombardier CRJ200 operated by Kazakh airline Scat, was carrying 16 passengers and five crew members, according to a statement posted on the prosecutor’s website. It was flying a domestic route between the northern city of Kokshetau and Almaty, Kazakhstan’s largest city, and crashed about three miles away from the airport.

According to Scat, the plane crashed while attempting to land in bad weather conditions. The weather near Almaty on Tuesday afternoon appeared to be foggy and humid, according to Weather.com.

The airline has promised to confirm the official cause of the crash once the plane’s black box flight data recorder is recovered.

President Nursultan Nazarbayev expressed his condolences on Tuesday to the families and friends of those killed in the crash, according to a statement on his website.

Kazakh authorities have opened a criminal case based on the violation of transportation safety rules resulting in the death of two or more people, the Prosectuor General’s office said in its statement.