VLADIVOSTOK, Russia -- Two military helicopters collided in mid-air in Russia's far east on Tuesday, killing six crew members and leaving one badly injured, emergency and Defense Ministry officials said.

Russian Defense Minister Sergei Ivanov blamed reckless behavior by pilots for the accident -- Russia's second helicopter disaster in the area in a week -- in which one Mi-24 sliced through the fuselage of the other.

"This was negligence, showing-off and air hooliganism," Ivanov was quoted as saying by Interfax News Agency.

Ivanov was in the region attending large-scale military exercises in the Pacific. He said an investigation into the crash had been launched.

The Defense Ministry said the two Mi-24s, which had been taking part in the exercises, were attempting to land at the Chernigovka airfield near the town of Ussuriisk, 20 km (12 miles) from the port of Vladivostok.

ITAR-TASS News Agency, quoting Far Eastern military command sources, said the two helicopters were flying close together and the rotor blade of one cut through the tail of the other. They crashed into each other and exploded, Reuters reported.

The Mi-24 rocket-firing helicopter gunship, nicknamed Crocodile by Russian forces, has played a prominent role in Moscow's campaign against separatist Chechen guerrillas. The accident happened just days after the governor of Sakhalin island, also in Russia's far east, and 19 others were killed in a helicopter crash.

Last year the governor of the Kransnoyarsk region and former presidential candidate Alexander Lebed died with six others in a helicopter crash in Siberia.