Two planes carrying dozens of parachutists collided in midair Thursday over western Slovakia, killing seven people, officials said. Slovak media reported 15 other parachutists missing and an aviation official said some reportedly survived by jumping out with their parachutes.

Zuzana Farkasova, a spokeswoman for the Slovak firefighters, said the accident that killed seven people took place Thursday morning about 1:20 a.m. ET near the village of Cerveny Kamen. Rescue workers were using helicopters to reach the crash site, in the White Carpathians mountain range that forms the border with the Czech Republic.

Juraj Denes, an official with the Slovak government agency that investigates plane crashes, said according to preliminary information, some 40 people were on board two L-410 planes at the time of the collision, which occurred at an altitude of 4,921 feet. He said those on board were parachutists.

Denes said some parachutists from one of the planes survived because they managed to jump out before the collision. He did not give a specific number of survivors.

The TA3 news television said 15 of the parachutists were still missing. It said all the parachutists were training for this weekend's air show in nearby Slavnica.

Slovak Health Minister Viliam Cislak and Interior Minister Robert Kalinak were heading to the crash site Thursday.