Russian officials believe rebels from the Caucasus region are to blame for the deadly suicide blasts that occurred on a pair of Moscow subway trains on Monday morning.

Officials say two female suicide bombers walked onto subway trains during the morning rush hour, before blowing themselves up in separate blasts. Thirty-eight people were killed, while another 65 people were injured.

The first blast hit the Lubyanka station in central Moscow, just before 8 a.m. local time.

Ludmila Famokatova, a woman who sells newspapers outside the station, said the people streaming out after the bombing appeared distraught, but not panicked.

"One man was weeping, crossing himself, saying: ‘Thank God I survived,'" she said.

The Lubyanka train station sits right below the headquarters of the Federal Security Service, the agency that replaced the former KGB.

The second blast came 45 minutes later at the Park Kultury station, across the street from two of Russia's major media organizations, RIA Novosti and RT.

Vladimir Markin, a spokesperson for Russia's top investigative body, said the Park Kultury bomber blew herself up just as the train doors shut. She was wearing a belt laden with plastic explosives. He told reporters that the woman was not immediately identified.

Alexander Vakulov, 24, said he was waiting on the opposite platform at the Park Kultury station when the blast occurred.

"I heard a bang, turned my head and smoke was everywhere," Vakulov said. "People ran for the exits screaming."

Valtin Popov, 19, also witnessed the blast from the opposite platform.

"I saw a dead person for the first time in my life," said Popov.

Following the violence, Russian Prime Minister Vladimir Putin vowed that "terrorists will be destroyed."

Russian President Dmitry Medvedev met with Federal Security Service head Alexander Bortnikov.

Medvedev said his country would "continue the fight against terrorism unswervingly and to the end."

Blasts draw attention

Fred Weir, a correspondent for the Christian Science Monitor, said the blasts were designed to draw the world's attention.

"It seems clearly that this was co-ordinated for maximum political impact," Weir told CTV's Canada AM during a telephone interview from Moscow on Monday morning.

Russian TV showed video of the smoke-filled Lubyanka station, where wounded and possibly dead victims were lying on the floor.

RT correspondent Charlotte Lomas-Farley was working at the TV station across the street from the Lubyanka station when the second blast hit.

"I have to say that everybody here in Moscow is very shocked at what happened," Lomas-Farley told CTV's Canada AM in a telephone interview from Moscow.

"They were scenes of utter panic and chaos earlier on this morning with people flooding the streets, very much hysterical, wanting to know what had happened and trying to get a hold of loved ones."

A few hours after the bombing, Lomas-Farley said the situation had calmed some, as authorities sent police to the bombing scenes, as well as to various transit stations.

Moscow's subway system carries about seven million passengers every day. Residents rely on the system to travel through Russia's sprawling capital city.

In Ottawa, Foreign Affairs Minister Lawrence Cannon said Canada "strongly condemns the cowardly attacks" on the Russian subway system. He said the Canadian government offers its "deepest sympathy" to the people whose family and friends had been hurt or killed in the attacks.

In Washington, U.S. President Barack Obama condemned the "heinous" violence in Moscow and offered his condolences to the Russian people. He said the U.S. stands united with Russia in its opposition to extremism.

The Moscow attacks prompted New York's transit system to beef up its own security on Monday. Spokesperson Kevin Ortiz said the city's transit agency had a "heightened security presence," but did not provide further details.

In London and Madrid, however, authorities said there were no immediate plans to increase security. Both European cities have suffered prior attacks on their transit systems.

Terror tremors

Moscow's battle with rebels in the Caucasus region has heated up recently, with Russian police reporting the death of one militant leader in the Kabardino-Balkariya region last week.

In February, Chechen rebel leader Doku Umarov told an interviewer that "the zone of military operations will be extended to the territory of Russia…the war is coming to their cities."

In the same interview, Umarov said his fighters were behind the November bombing of a passenger train that killed 26 people.

The Associated Press reported Monday that at least three al Qaeda-affiliated websites posted messages that praised the Moscow subway attacks.

Terrorism expert Alan Bell said Russia worked to drive many Chechen rebels out of Chechnya about two years ago, as part of an intensive crackdown on their activities.

But the rebels ended up regrouping in North Caucasus, which has bred the current problems in that region, he said.

Neither Putin, nor Medvedev, made mention of any specific actions that Moscow would take in the Caucasus region, though Bell suggested that the government will not hesitate to act.

"The Russians don't mess around with terrorism like a lot of other countries do," Bell told CTV's Canada AM during an interview in Toronto.

"When something happens, they will go in, they will find who is responsible and they will deal with this in a very cut and dried manner."

With files from The Associated Press