A Russian airliner crashed and another apparently broke up in the air almost simultaneously after taking off from the same airport, killing all 89 people aboard and raising fears of a terrorist attack. Rescuers found wreckage from a Tu-154 jet with at least 46 on board about nine hours after it issued a distress signal _ possibly signaling a hijacking _ and disappeared from radar screens over the Rostov region some 1,000 kilometers (600 miles) south of Moscow. At about the same time the Tu-154 disappeared, a Tu-134 airliner carrying 43 people crashed in the Tula region, about 200 kilometers (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 the press center of the Federal Security Service, or FSB, said initial investigations at the crash sites had not turned up signs of terrorism. "At the moment, the main scenario under consideration is that of a violation of the rules of civilian aircraft use," the Interfax news agency quoted FSB spokesman Nikolai Zakharov as saying. He said among the possible causes were technical failures, the use of poor-quality fuel, a violation of fueling rules and pilot error. Earlier, the ITAR-Tass news agency quoted chief FSB spokesman Sergei Ignatchenko as saying authorities suspected the crashes were caused by "illegal interference in civil aviation activity," and an FSB duty officer said Ignatchenko had not ruled out terrorism. The two planes left Moscow's Domodedovo airport within 40 minutes of each other Tuesday night and disappeared from radar screens in the space of a few minutes around 11:00 p.m. (1900 GMT), officials said. President Vladimir Putin ordered an investigation by the FSB _ the nation's main intelligence agency _ and police officials said security was being tightened at Russian airports as well as other transport hubs and public places. FSB experts were trying to determine whether explosions proceeded the crashes, the Interfax news agency reported.
