A Russian airliner crashed and another apparently broke up in the air almost simultaneously after taking off from the same airport, officials said, killing all 89 people aboard and raising fears of a terrorist attack.
Authorities said rescuers found wreckage from a Tu-154 (search) jet with at least 46 on board, about nine hours after it issued a distress signal and disappeared from radar screens over the Rostov (search) region some 600 miles south of Moscow.
At about the same time that plane disappeared, a Tu-134 airliner carrying 43 people crashed in the Tula (search) region, about 125 miles south of Moscow, officials said. Emergency officials said there were no survivors from either plane.
Officials made conflicting statements about whether the signal from the Tu-154 indicated a hijacking or another severe problem on the aircraft, and there was bad weather overnight in both areas.
President Vladimir Putin (search) ordered an investigation by the nation's main intelligence agency, the Federal Security Service, and security was tightened at airports across the country.
Authorities have expressed concern that separatists in war-ravaged Chechnya could carry out attacks linked to this Sunday's election to replace the region's pro-Moscow president, who was killed by a bombing in May. Rebels have been blamed for a series of terror strikes that have claimed hundreds of lives in Russia in recent years.
Witnesses said they heard what sounded like three explosions before the first plane crashed and suspicions of terrorist involvement were compounded when officials said the Sibir airlines Tu-154 had issued a signal indicating the plane was being seized.
The Interfax and ITAR-Tass news agencies later quoted an unnamed law enforcement source as saying that the signal was an SOS and that no other signals were sent.
But Oleg Yermolov, deputy director of the Interstate Aviation Committee, said that it is impossible to judge what is behind the signal, which merely indicates "a dangerous situation onboard" and can be triggered during a hijacking or a potentially catastrophic technical problem.
Interfax reported that emergency workers spotted a fire in the Rostov region, where the Tu-154 went missing. But rainy weather hampered the search efforts and it took hours before any wreckage was found. A flight data recorder from the plane was recovered, Emergency Situations Minister Sergei Shoigu said, according to Interfax.
The regional Emergency Situations Ministry chief Viktor Shkareda told AP the plane apparently broke up in the air and that wreckage was spread over an area of some 25-30 miles. Body parts have also been found along with fragments of the plane, Interfax quoted federal Emergency Situations Ministry as saying. It said the parts were found near Gluboky, a village north of the regional capital Rostov-on-Don.
Shkareda said 52 people were aboard the plane, while emergency officials in Moscow put the number of passengers and crew at 46.
In the Tula region, rescuers found fragments of the Tu-134 jet's tail near the village of Buchalki. Emergency Situations Ministry spokeswoman Marina Ryklina said later there were no survivors.
At about the same time that the Tu-134 crashed, the Tu-154 lost contact with flight controllers, Ryklina said. Interfax, citing Russia's Interstate Aviation Committee, said 44 passengers and an unknown number of crew were abroad.
The Tu-154 took off from Moscow's Domodedovo airport at 9:35 p.m. Tuesday and the other plane left 40 minutes later, state-run Rossiya television reported.
The Tu-154 belonged to the Russian airline Sibir, which said that the plane had been in service since 1982.
Quoting unnamed aviation officials and security experts, Russian news agencies said authorities were not ruling out terrorism and suspicions were heightened by the fact that the two planes disappeared around the same time.
ITAR-Tass reported that the authorities believe the Tu-134 fell from an altitude of 32,800 feet. It said the plane belonged to small regional airline Volga-Aviaexpress and was being piloted by the company's director, and quoted dispatchers as saying 34 passengers and seven crew were aboard. Ryklina put the numbers at 35 and eight -- a total of 43.
Interfax quoted a Domodedovo airport spokesman as saying no foreigners were on the passenger lists for either plane.
Authorities said the Tu-134 was headed to the southern city of Volgograd, where Volga-Aviaexpress is based, while the plane that crashed in the Rostov region was flying to the Black Sea resort city of Sochi, where Putin is vacationing.
When Russia's U.N. Ambassador Andrey Denisov was told of the initial report of two near-simultaneous crashes, he said, "Now we have to see if there's terrorism."
In Washington, a U.S. official, speaking on condition of anonymity Tuesday evening, said it was the understanding of American officials that the two Russian planes disappeared within four minutes of each other, which "in and of itself is suspicious."