At approximately 11 p.m. the two aircraft disappeared from radar screens. Prior to crashing near Rostov-na-Donu, some 1,000 kilometers south of Moscow, the TU-154 sent a distress signal indicating a possible attack.
The regional Emergency Situations Ministry chief told AP that the plane apparently disintegrated in the air and that wreckage was scattered over an area of 40-50 kilometers.
The second aircraft, the Tu-134, crashed in Tula Oblast about 200 kilometers south of Moscow. Witnesses reported seeing an explosion before the plane fell.
Meanwhile, a terrorist group calling itself the Islambouli Brigades posted a statement on a website on 27 August claiming responsibility for blowing up the two jets, AP and other media reported. The group's statement blames the Russians for "slaughtering Muslims" in Chechnya. It claimed that there were five "mujahedin" aboard each plane and that information about them will be published soon. The statement did not provide further details of the attacks.
On 31 July, a group by the same name claimed responsibility for the attempted assassination of Pakistani Prime Minister-designate Shaukat Aziz. The group claims to be connected with Al-Qaeda and it is believed to be named after Khaled Islambouli, the leader of a group that assassinated Egyptian President Anwar Sadat in 1981.
Russian officials at first appeared to blame human error for the crash. Russian RTR television ran a 10-minute news bulletin at 10 a.m. on 25 August featuring Sergei Ignatchenko, spokesman for the FSB's press office, who said: "Several versions are under investigation. The main version is that civil aviation rules were breached. The version that a terrorist act was to blame is also being looked into, but currently there is no evidence to back it up."
Ignatchenko went on to tell viewers that "poor fuel quality, pilot error, or inclement weather conditions" were among other possible causes of the crashes.
Experts told "The New York Times" on 26 August that the chances of two pilots making errors and bringing down their planes at the same time were highly unlikely. "That's pretty far out there on the chance bar," said Bob Francis, former vice chairman of the U.S. National Transportation Safety Board.
AP cited Jim Burin of the U.S.-based Flight Safety Foundation as saying that although "bad fuel" could cause an airplane's engines to fail, this would probably be noticed and reported by the crew early on, as the engines began to labor or misfire. He also said that initial reports from the crash scenes indicated that one plane's wreckage was spread out more widely than would normally be the case in a crash that was not preceded by an explosion, AP reported on 26 August.
The same day, Radio Rossii reported that an anonymous Russian expert said that it was virtually impossible for a TU-134 airplane to disintegrate in midair. "We were told on conditions of anonymity in the Gromov Flight Research Institute that the nature of the debris from the crashed Tu-134 that has already been found brings to the fore the possibility of a powerful external influence on the fuselage of the plane."
On 25 August, Russian Emergency Situations Minister Sergei Shoigu said that "one of the flight recorders from the Tu-134 has been found in good condition and the search for the second flight recorder is ongoing...."
On 26 August, RTR television contradicted Shoigu and announced that the flight recorders were found in poor condition and had to be reconstructed. A video of what was purported to be a destroyed flight recorder with recording tape in shreds laying on a table was broadcast on 27 August on RTR.
Investigators told RIA-Novosti on 26 August that the flight-data recorders aboard the planes have been recovered but that some of them are damaged and it will take "some time" to recover the data, depending on how extensive the damage is. Investigators said earlier that preliminary information from the recorders would be released on 26 August.
By the evening of 26 August another indication was revealed that the planes might have been destroyed by an act of terror. Interfax cited Transport Minister Igor Levitin, who is heading the government commission investigating the two crashes. as saying that the commission "is checking, among other things, reports that none of the relatives of a woman passenger by the name of Dzhebirkhanova have inquired about her" after the Tu-154 crash.
A source on the commission told Interfax that its first conclusions would be issued by 30 or 31 August. If so, this would take place after the 29 August presidential elections in Chechnya.
Chechen rebels have repeatedly threatened to disrupt these elections. And while no Chechen group has taken credit for these acts, if rebels were indeed responsible for the double disasters on 24 August this would be a major blow to the Kremlin and the credibility of the FSB.