MOSCOW (AP) -- An explosion ripped through a Moscow subway car during rush hour Friday morning, killing 39 people and wounding more than 100 in what appeared to be the deadliest terrorist blast to hit the capital since Russia launched its second war in Chechnya.
Officials differed over whether the blast had been caused by a suicide bomber. Deputy Moscow Mayor Valery Shantsev said that investigators had not found metal shrapnel, which usually fills suicide bombers' explosives. He said that the bomb had likely been in a suitcase or backpack on the floor of the subway car, the ITAR-Tass news agency reported.
Moscow has been on alert following a spate of suicide bombings that officials have blamed on Chechen rebels. The latest was in December, when a suicide bomber blew herself up outside a hotel across from Moscow's Red Square, killing at least five bystanders.
The Interfax news agency, citing unidentified police sources, said the attack was carried out by a female suicide bomber. Police have a videotape of the suspected attacker and her alleged accomplice standing on a platform before boarding the train, Interfax reported.
President Vladimir Putin appealed to the international community to boost its efforts in the fight against terrorism, which he called ``this plague of the 21st century.''
``Russia doesn't conduct negotiations with terrorists - it destroys them,'' he said in televised remarks.
Putin said the explosion could be linked with the March 14 presidential election, which he is expected to win easily, and intended to put ``pressure on the present head of state.''
Friday's blast struck the second car of a train after it pulled away from the Avtozavodskaya station, heading northwest to the Paveletskaya station on the Moscow metro's busy circle line.
After the explosion, the train traveled several hundred more feet before coming to a stop, police spokesman Kirill Mazurin said in a TV interview.
The blast was equivalent to 11 pounds of TNT, Shantsev said.
Valery Draganov, a member of parliament representing the Avtozavodskaya district, told Echo of Moscow radio that body parts were scattered along the tracks. Inside the badly damaged wagon, bodies sat side-by-side still in their seats, and covered in soot.
The line where the explosion occurred is one of Moscow's deepest underground, and the wounded were brought up on stretchers on the long escalators to ambulances crowded outside the entrance to the Avtozavodskaya station, southeast of downtown Moscow.
The explosion sent clouds of smoke through the tunnel and there were conflicting reports about whether a fire had broken out.
Deputy Interior Minister Alexander Chekalin said at least 39 people were killed, and Shantsev said 120 were injured seriously enough to be treated at hospitals.
More than 700 people were evacuated, the ITAR-Tass news agency reported, citing metro staff. The majority of Russians are dependent on public transportation, and the spacious train cars are usually packed tight during rush hour.
``I heard a loud sound ... and smoke filled the car,'' said Ilya Blokhin, 31, a doctor who was on the train, several cars away from the blast. ``What are our country and government and police going to do when they blow up crowded subway cars?''
An unidentified woman, blood covering her face, told NTV television that passengers were unable to open the door of the subway car for a time after the explosion. After finally prying open the door, she said they walked more than a mile out of the tunnel.
``It's scary to live here,'' said Galina Abramova, a passenger on a train that was coming in the opposite direction when the explosion occurred. ``I wasn't that close to the train but I feel scared anyway ... now at noon, my feet are still weak.''
Police immediately barricaded the two metro stations closest to the train and stopped all traffic on the entire line. Dozens of buses were rerouted to carry the passengers evacuated from the subway, clogging streets.
Rossiya television said Moscow Mayor Yuri Luzhkov was cutting a U.S. trip short to return.
U.S. Ambassador Alexander Vershbow condemned the attack and said the United States was ready to offer assistance if requested. Condemnations also poured in from European capitals and former Soviet republics.
No group claimed responsibility, but Chechen rebel leader Shamil Basayev has claimed to have masterminded the most recent terrorist explosions in Russia.
In addition to the December blast outside the National Hotel, two suicide bombers blew themselves up at a Moscow rock concert last July, killing themselves and 14 other people. Five days later, an aborted suicide bomb attack at a central Moscow restaurant killed a disposal expert who was trying to defuse the bomb. The woman who had carried the bomb was arrested and is awaiting trial.
A bombing in a Moscow subway car in June 1996 killed four people, and another injured at least nine in a busy metro station in February 2001.
In August 2000, a bomb exploded at a crowded pedestrian underpass filled with kiosks at Pushkin Square, a popular meeting place near several metro stations in the heart of Moscow. The attack was initially blamed on Chechen rebels, but some police later said that a turf battle between rival businessmen or criminal gangs could have been the motive.
