MOSCOW, Feb. 6 (Xinhuanet) -- The death toll from the explosion that occurred aboard a subway train during the morning rush hour of Friday in the Russian capital rose to about 40.

    The explosion killed about 40 and injured about 100 others, Interfax news agency reported, citing city emergency service sources.

    Officials with the Federal Security Service (FSB) believed that the blast, in the second wagon of the train heading for the station of Avtozavodskaya in southeast downtown Moscow from Paveletskaya near the city center, was probably caused by a suicide bomber.

    Law enforcement agencies quoted eyewitness as saying that an explosive device filled with shrapnel was detonated by a female suicide terrorist in the carriage at around 8:40 a.m. Moscow time (0540 GMT).

    The explosion, said to be equivalent to over 1 kg. of TNT, caused an extensive fire and badly damaged the carriage with reportedly some 100 passengers on board. Some 700 passengers aboard the train have been lifted to the ground, Itar-Tass news agency cited FSB as saying.

    The fire has now been put out. The coach was so badly damaged that it is impossible for rescuers to haul it out from the site of the blast.

    The train's staff reported the first data on the explosion but communications with them was lost, FSB sources said.

    Rescuers and some 130 emergency buses are evacuating stranded passengers. Traffic on the subway line where the blast occurred has been suspended. At least 50 ambulances were outside the entrance to the Avtozavodskaya station. Moscow hospitals were put on alert.

    The Interior Ministry has reinforced security measures in Moscow's metro system to prevent new terrorist acts, a deputy minister said. Enditem