As the next of kin are grieving their losses and the wounded are groaning their pains, the Muscovites and the city subway commuters in particular are grappling with the fear arisen from the terror bombing attacks against the Moscow metro again.

Monday's twin blasts were the latest and they claimed the lives of at least 38 and wounded over 60 people, posting the second deadliest attack against the metro system which, with 12 routes stringing up 180 stations, is one of the busiest in the world.

Six years ago also during the morning rush hour, a blast ripped through a crowded subway carriage car, killing 42 people and wounding more than 250 others.

The city reported its first terror bombing attack against the metro back in 1998 and municipal authorities have been posting police and security personnel at subway stations as security measures.

Yet security loopholes are just obvious as any traveler will find out that no compulsory baggage checks are required at entrances and the posted police and security personnel just rely on the closed-circuit TV system to monitor the passenger flow which mills around in the vicinity of 8 million a day.

Metro police told Xinhua that they do have security check facilities but they are used only to inspect unattended and suspicious objects.

Security specialists argue that even if baggage checks are made compulsory, there is still no ready device to check against those strap-on explosive devices probably used by the two female suicide bombers who attacked the metro on Monday.

The extremists would just go to extremes to do whatever they see fit for their purposes.

Russian security intelligence has already linked the two suicide bombers to the North Caucasus, the center of an Islamic extremist insurgency against Moscow.

"We'll consider it as the basic version because the bodies of two female suicide bombers who were residing in the North Caucasus have been found," said Alexander Bortnikov, head of the Russian Federal Security Service.

Though he did not mention al-Qaida, Russian Foreign Minister Seigei Lavrov hinted links to militants on the ungoverned Afghan-Pakistan border, where al-Qaida militants and Taliban insurgents are hiding.

"We know that many people there actively plot attacks, not just in Afghanistan, but also in other countries. Sometimes the trails lead to the Caucasus," Lavrov said.