A Russian heavy-lift military cargo plane crashed on takeoff Sunday in Siberia, killing all 11 crew members on board, officials said.

The crash was the second accident in less than a month involving an Il-76 , the mainstay of the Soviet and Russian air force since the 1970s. These and a string of other accidents have raised concerns about the condition of Russia's aging fleet of Soviet-built aircraft.

The cause of Sunday's crash was not yet known. The four-engine plane had just taken off from Mirny in the Sakha Republic when it banked to the right and was unable to gain altitude, said Vasily Panchenkov, a spokesman for the Interior Troops, which were flying the aircraft.

The plane hit a slag heap from an old mine and crashed, exploding on impact, he said. The plane, which was headed to Irkutsk, was carrying no cargo but its fuel tanks were full.

The Il-76 crashed about a mile from the runway in open fields. No one on the ground was reported hurt.

The bodies of all 11 crew members were recovered, Panchenkov said.

Flying conditions were good, with clear skies, light winds and temperatures of minus -11 Fahrenheit, he said.

Federal investigators were on the scene and said they have recovered the aircraft's flight recorders. State television showed the charred remains of the giant aircraft scattered across the snow.

Russia's air force had temporarily grounded all Il-76 aircraft after an engine broke off the wing of a plane on Oct. 7 as the pilot engaged full throttle in preparation for takeoff. No one was hurt in that accident.

The ban was to have remained in place until experts could determine what caused the engine to break off and could check the fleet's condition. No information was available Sunday from the Defense Ministry.

The Il-76 has four engines mounted under its wings and is capable of carrying 44 U.S. tons of big cargo, such as armored vehicles.

The Russian air force also has a small number of the world's biggest An-124 Ruslan transport planes along with smaller and older An-12 turboprop transports, but it relies on the Il-76 for most of its heavy-lift capability.

Earlier this year, the air force announced that it had grounded its fleet of Mig-29 fighter jets and had to carry out costly repairs to make them safe to fly. The move followed a crash in December that occurred when a plane lost part of it tail section. Officials said the accident had been caused by corrosion.

Despite a steady rise in defense spending during Russia's eight-year, oil-driven economic boom, the military has received only a few new aircraft and has had to continue to rely on aging Soviet-built planes.