Though no group has so far claimed responsibility for Monday's terror attacks, police had reportedly warned of a potential bombing attack by militants from Chechnya.

State Duma security committee chief Vladimir Vasilyev took the bombing as a terrorist retaliation against the law enforcement launched by Russian President Dmitry Medvedev in the restive republic, where four militant leaders and dozen rebels were killed by Russian troops recently.

Security specialists in the country have been facing a tortuous if not outright uphill struggle with the rebels, militants and terrorists in the North Caucasus and from the mountainous Afghan-Pakistan border, where the disgruntlement and hostility accumulated over the years will not be dispersed overnight.

Already seeing it as the vital security threat, President Medvedev decided to establish a special federal district out of the North Caucasus, so as to solve its issue of impoverishment along with clan rivalry and militant violence.

To show his special attention to the region, the Russian president even appointed the governor of the new federal district his special envoy to the turbulent region as well as a deputy prime minister of the country.

But Monday's bombing attacks against the Moscow metro have not only brought the fear of terrorism right into the heart of the country again, they are forcing the security authorities to reconsider stepped-up fight against terrorism so as to appease public concerns.

Russians, however, will have to question the security mechanism which was exposed to have problems at both ends of its security chain.

If the authorities cannot easily deal with the terror-minded rebels and militants in their backyards, Russians may wonder, can't they do better in Moscow to beef up the security along the public transport system?