Two blasts have gone off during morning rush hour in Moscow's underground subways, killing dozens of morning commuters. Via RT.com:

The first explosion happened in a carriage at the central Lubyanka underground station and has claimed the lives of 26 people, with more injured, informs RIA Novosti news agency.

The second blast happened at the Park Kultury Metro station in the third carriage of a train. 15 or more people are reported to be dead, the quantity of injured is unknown.

According to Russia’s Emergency Ministry, the first explosion presumably happened in the second carriage of a Metro train stopped at the Lubyanka station in the very center of Moscow, only several hundred meters from the Kremlin. At 9:30am Moscow time, the Emergencies Ministry gave the number of casualties as 20 to 25 killed and 17 wounded on Lubyanka station, and 12 to 15 killed and over 20 wounded at Park Kultury station.

Officials are investigating the possibility of suicide bombers and/or a coordinated terrorist attack. The video has some stunning photos and video taken by eyewitness and people in close proximity. On a Monday morning rush-hour commute, there's a high likelihood that many more have died than initially reported.

Telegraph.co.uk reports:

Though it has yet to be confirmed, security sources said early indications suggested suspected suicide bombers from the volatile North Caucasus region that includes Chechnya were to blame.

If that is right, it would be the first time since 2004 that they have struck the Moscow metro. Prosecutors opened a criminal case immediately, saying they would be working on the basis that the explosions were the work of terrorists.

Reporters are updating at RT.com as more information is known. Other sources: MSNBC, CNN

Update #1: Video shot of the scene above ground.

Update #2: CBS News now quotes Moscow mayor as attributing both blasts to female suicide bombers.

Update #3: Via STRATFOR:

According to STRATFOR sources in Moscow, the two locations of the attacks on the subway in the city are symbolic. The first attack in Park Kultury is symbolic in that it is one of the city’s cultural centers being located near Gorky Park. The second location of the attack at the metro station of Lubyanka is nearly under the Federal Security Bureau’s headquarters—former KGB headquarters—the security hub of Russia. According to media reports, the attacks were caused by suicide bombers at the peak of rush hour in Moscow. Thus far, rumors are flying that Muslim extremists are responsible for the attack. In the past, there have typically been spring-summer attacks in Moscow in February, and spring is just now arriving in the capital.