Alexander Natruskin / Reuters

A woman crying as Interior Ministry officers block her way in front of the exit of Lubyanka metro station in Moscow on Monday, March 29.

At least 38 people were killed and 70 wounded on Monday when suicide bombers detonated explosives filled with bolts and iron rods on two packed Moscow metro trains during the morning rush hour, the worst attack in the Russian capital in six years, officials said.

(More photos from both scenes can be found here)

No group immediately claimed responsibility for the blasts but suspicion was likely to fall on groups from the North Caucasus, where the Kremlin is fighting a growing Islamist insurgency.

The first blast just before 8 a.m. tore through the second carriage of a train as it stood at the Lubyanka metro station, close to FSB headquarters. It killed at least 23 people.

Another blast about 40 minutes later wrecked the second carriage of a train waiting at the Park Kultury metro station, killing 14 more people.

"Two female terrorist suicide bombers carried out these bombings," Moscow Mayor Yury Luzhkov told reporters at Park Kultury metro station.

Russian civil aviation authorities ordered increased security at airports, fearing further actions.

Surveillance camera footage posted on the Internet showed motionless bodies lying in Lubyanka station lobby and emergency workers treating victims.

The Moscow metro system is one of the world's busiest, carrying about 7 million passengers on an average workday, and is a key element in running the sprawling and traffic-choked city.

The blasts practically paralyzed movement in the city center as emergency vehicles sped to the stations. Helicopters hovered over the Park Kultury station area, which is near the famous Gorky Park.

Service on the Red Line, on which both stations are located, has been suspended from Park Kultury to Komsomolskaya. 

Passengers, many of them in tears, streamed out of the station, one man exclaiming over and over "This is how we live!"

At least a dozen ambulances were on the scene.

A source told RIA-Novosti that dozens of Moscow residents and visitors turned to doctors with nervous breakdowns and heart attacks after witnessing the blasts. The Emergency Situations Ministry has opened several hotlines for anyone seeking psychiatric help as a result of the explosions; people can call 626-3707, 632-9671 or 632-9673. The ministry's web site also has numbers for hospitals treating victims.

Witnesses spoke of panic at the stations, with people falling over each other in dense smoke and dust as they tried to escape.

"I was in the middle of the train when somewhere in the first or second carriage there was a loud blast. I felt the vibrations reverberate through my body," an unidentified man who was on the train at Park Kultury told RIA-Novosti in a video interview.

"People were yelling like hell," he said. "There was a lot of smoke, and in about two minutes everything was covered in smoke."

"I was moving up on the escalator when I heard a loud bang, a blast. A door near the passage way arched, was ripped out and a cloud of dust came down on the escalator," a man named Alexei told state-run Rossiya 24 news channel.

"People started running, panicking, falling on each other," he said.

The ruble fell to 34.25 from 34.13 against the Central Bank's dollar-euro basket. Russian equity markets opened down 0.15 percent.

Prosecutors said they had opened an investigation. 

Prime Minister Vladimir Putin, speaking from the Siberian city of Krasnoyarsk, vowed to punish those responsible for the attacks.

"A crime that is terrible in its consequences and heinous in its manner has been committed," Putin said at the start of a video conference with senior emergency officials.

"I am confident that law enforcement bodies will spare no effort to track down and punish the criminals. Terrorists will be destroyed," he said. The prime minister cut short his visit to Krasnoyarsk and returned to Moscow.

Putin also signed a decree Monday allocating compensation funds to families of the bombings as well as people who were injured, Interfax reported. According to the decree, families of those who died will receive 300,000 rubles ($10,122) plus 18,000 rubles for funerals while those who were seriously injured will receive 100,000 and those who were only slightly injured will receive 50,000.

President Dmitry Medvedev on Monday ordered senior officials to fight terrorism "without hesitation, to the end."

Medvedev said Russia will act without compromise to root out terrorists and ordered security to be boosted across the country.

He said human rights must be respected during police operations, a Kremlin spokesman said.

The current death toll makes it the worst attack on Moscow since February 2004, when a suicide bombing killed at least 39 people and wounded more than 100 on a metro train.

Chechen separatists were blamed for that attack.

Russian police have killed several Islamic militant leaders in the North Caucasus recently, including one last week in the Kabardino-Balkariya region. The killing of Anzor Astemirov was mourned by contributors to two al-Qaida-affiliated web sites.

The killings have raised fears of retaliatory strikes by the militants.

In February, Chechen rebel leader Doku Umarov warned in an interview on a rebel-affiliated web site that "the zone of military operations will be extended to the territory of Russia ... the war is coming to their cities."

Umarov also claimed that his fighters were responsible for the November bombing of the Nevsky Express passenger train that killed 26 people en route from Moscow to St. Petersburg.

(AP, Reuters, MT)