Two airline crashes in Siberia over the weekend killed 26 people, and early reports indicate that overloading -- a recurring problem in Russian aviation -- may have been to blame.


The two accidents are the fifth and sixth of the year over Siberia, bringing the total of people killed in air disasters there to at least 296. Last year 222 were killed nationwide, which in itself was a major increase over previous years.


The crashes come shortly after a U.S. Embassy ban on employee travel on Russian carriers, sparked by the earlier air disasters. A joint Russian-American review of Russian aviation completed last month gave the industry minimally passing marks for safety and resulted in a partial lifting of the ban.


One of the downed planes, an Antonov-12 cargo hauler, belonged to Aeronika Airlines, a carrier approved for travel by the U.S. Embassy. The plane, en route from South Sakhalin to Yermolino in the Kaluga region, burst into flames two kilometers short of the runway Saturday afternoon, Interfax reported. According to the Interstate Aviation Committee, 21 people died.


Although Interfax reported that the plane was carrying 12 tons of fish products and four automobiles, Dennis Cooper, who represents the U.S. Federal Aviation Administration in Moscow, said the plane may also have had 10 unauthorized passengers.


Vladimir Kofman, a spokesman for the aviation committee, said the investigators have found the plane's black box, but that it was too early to pinpoint a cause. The Russian-American safety report, however, highlighted overloading as a frequent cause of air disasters.


The other crash, involving an Antonov-2, a small biplane with one engine, occurred Saturday morning in the Yakutia village of Batagai. The plane, part of the Yakutavia Airline fleet, crashed after an engine caught fire on takeoff. Five passengers, one a child, were killed.


On Monday, the Russian news agency RIA said local investigators learned the plan was carrying 17 passengers, though only 12 were registered. It is unclear whether Yakutavia is on the U.S. list of approved carriers.


There is no reason to believe that Siberia is more dangerous to fly in than anywhere else in Russia, said Alexander Neryadkov, deputy director of certification and investigation at the Department of Air Transportation.


"None of the crashes can be linked to the area," he said. "They all happened for completely different reasons." He added, though, that the An-2, an old plane, was known to have problems with engine failure.


Major crashes in Siberia this year:


?In January, 125 people died when a Tu-154 belonging to Baikal Airlines crashed en route from Khabarovsk to Moscow.


?In March, 75 people died when an Airbus-A310 crashed near Novokuznetsk en route to Hong Kong. The investigation report has yet to be issued, but it has been determined the pilot was giving his children a flying lesson.


?In August, 47 people died when an An-12 military transport plane nicked a hill and crashed near the Chinese border.