As many as 18 people are feared dead after a Russian cargo plane apparently exploded and crashed in the Far East region of the country. It was the latest in a series of air disasters in Russia in recent weeks.

Witnesses say they saw two explosions rip through the cargo plane before it plummeted in flames near the city of Okhotsk.

The pilot of the Ilyushin IL-76 aircraft told air traffic controllers he was trying to make an emergency landing because of an onboard fire, before the explosions occurred.

Rescue crews say the plane had broken into three parts when they found flaming wreckage and cargo strewn over a large area.

Those on board included five men serving in Russia's border guard service, which had chartered the plane. The Il-76 is one of the most common cargo planes in Russia.

The crash is the latest of several air disasters recently in Russia. Saturday, 18 servicemen were injured when a helicopter fell more than 1,000 meters after an engine failure.

Two weeks ago, a smaller Ilyushin plane crashed north of Moscow, killing 27 people. And two weeks before that, five servicemen died when their military helicopter crashed into a radio tower.

The worst disaster so far this year occurred in July, when a Tupelov TU-154 passenger jet crashed in a Siberian forest, killing 145 people. That disaster prompted President Vladimir Putin to order a review of all safety procedures.

Exerts say air crashes have become increasingly frequent because of a lack of maintenance as well as aging planes and equipment. Many aircraft in the Russian fleet were built before the collapse of the Soviet Union 10 years ago.

Economic problems are also cited as a factor, as many air carriers lack the money to properly maintain their aircraft or purchase new planes.