SOFIA, Bulgaria (AP) — A Bulgarian military jet crashed on Friday during a drill for an airshow marking the anniversary of the country joining NATO, authorities said. Both pilots aboard the aircraft were killed.

The L-39 Albatros training jet went down shortly after noon near Graf Ignatievo Air Base in southwestern Bulgaria, around 150 kilometers (90 miles) from the capital of Sofia, the Ministry of Defense said.

The crash ignited a fire on the ground. Officials say efforts are underway to contain the blaze and an investigation has started into the cause of the crash.

A statement from the press department of Prime Minister Glavchev said he was on his way to the base.

Bularia is marking the 20th anniversary of its NATO membership on Saturday, and also 35 years since the MiG-29 was inducted into the Bulgarian Air Force, according to state news agency BTA.

Following the crash, Defense Minister Atanas Zapryanov cancelled the airshow. A statement from him was expected later on Friday.

Video from the state broadcaster BNT shows a large plume of black smoke rising above an airfield with fire trucks rushing toward the crash site.