MOSCOW. Aug 30 (Interfax-AVN) - Investigators have found traces of explosives in fragments of the TU-134 Crusty, one of the two jets that crashed in Russia almost simultaneously overnight to August 25, killing 90 people, Federal Security Service (FSB) spokesman Sergei Ignatchenko said.
On Friday, the FSB said traces of the same explosive - cyclonite - had been found in the wreckage of the other plane, the TU-154 Careless.
"Traces of cyclonite were found in the course of an additional investigation of fragments of the TU-134 airplane that crashed in the Tula region," Ignatchenko told Interfax on August 28.
The day before, he said traces of explosives had been found in the TU-154 wreckage and that a "preliminary analysis had shown it is cyclonite."
"Investigative operations have produced data that make it possible to identify a range of persons who may have been involved in the terrorist act aboard the TU-154 plane," he added.
"On instructions from the Russian president, the FSB is studying international experience of combating terrorism on air transport," he said.
"In particular, it is planned to use the checking and flight security control system that is used in Israel and is considered the most effective in the world," he said.
The TU-154 crashed in the Rostov region.
Both Tupolev liners had taken off from Moscow's Domodedovo airport.
"On the basis of all the data that have been collected, the prosecution service will make a decision on the possibility of requalifying the criminal proceedings as a terrorism case," Ignatchenko said.
The current proceedings are based on investigations into suspected offenses against laws on air traffic security and use of aircraft.
The Prosecutor General's Office said the investigations might end up in the same court case.