Traces of explosives found on both planes

The Russian press was quick to paint the pair as the latest in a line of female suicide bombers from the strife-torn Caucasus republic to strike, citing their suspected ethnic origins and the fact no relatives have come forward to claim their remains.

The crashes reinforced fears of attacks by Chechen extremists on an already nervous Russian public, with officials now suggesting Russia should copy the stringent security measures used by Israel on its flights.

While security services have made no link between the two women and the crashes, traces of the powerful explosive Hexogen were found in the fragments of both planes that crashed on flights to southern Russian cities late Tuesday.

"An additional analytical examination of fragments of the Tu-134 plane, which crashed Tuesday in the Tula district, showed traces of Hexogen," a spokesman for Russia's FSB intelligence service said, according to Russian news agencies.

The same substance had been found a day earlier in the other plane, which fell to the ground near the city of Rostov-on-Don at an almost identical moment. Officials have already described that crash as an act of terror.

For the press, however, there was no doubt who was responsible for the attacks, which came just days ahead of Sunday's presidential elections in Chechnya to replace murdered president Akhmad Kadyrov.

The daily Izvestia spoke to an official in the home town of one of the women -- a 27-year-old named as Amanta Nagayeva -- who told the paper that one of her brothers had been taken away by security forces four years ago and never been heard of since.

"Amanta Nagayeva had a clear motive to die: by blowing herself and the plane up she avenged herself for her brother," it said, commenting that several past suicide bombings in Russia had been carried out by the wives or sisters of Chechen fighters. The picture on the front page of the daily Kommersant -- the eyes of a Muslim woman peering out between the narrow slit of a veil -- was intended to lead its readers to only one conclusion.