Two explosions hit the Moscow subway system on Monday morning, killing at least 37 people, Russian news agencies reported.

The Emergency Situations Ministry said the blast which struck the Lubyanka station at 7:56 a.m. (0356 GMT) had killed 25 people and injured at least 10 others, the Itar-Tass news agency reported.

Prosecutors have opened a criminal probe into possible acts of "terrorism" after the deadly blasts.

Preliminary investigation showed female suicide bombers were responsible for the twin blasts, said Moscow Mayor Yury Luzhkov.

A police source cited by the RIA Novosti news agency said: "Parts of the body founded at the scene allow us to say that it was a woman."

The subway blasts that rocked Moscow's Lubyanka and Cultural Park stations were equivalent to the force of 2-3 kg of TNT each, said Moscow prosecutor Yuri Semin.

Semin said in the first blast, "the explosive device was tied to a suicide bomber."

However, it was also suspected that the blasts may have been coordinated and may have been triggered by a cell phone.

A spokesperson of the ministry told Itar-Tass that 14 people died in the wagon of the train and 11 on the platform.

Shortly afterwards, an explosion hit another subway station. Itar-Tass said at least 12 people were killed and 12 others injured in the second blast that hit the Cultural Park subway station at 8:40 a.m. (0440 GMT).

Xinhua reporters on the scene said the traffic around the two subway stations have been blocked, with dozens of ambulances and vehicles of investigators. A helicopter was evacuating the injured.

Most of the injured were "in critical conditions," said an official from the Moscow municipal government.

Both stations are on the same subway "redline" that runs through central Moscow, which has now been shut down.

Russian Prosecutor General Yuri Chaika will directly supervise the investigation into the blasts, said a spokeswoman for the Prosecutor General's Office.

On Feb. 6, 2004, at least 41 were killed and more than 130 others injured when a blast ripped through a crowded metro car in the Russian capital during the morning rush hour.