Doku Umarov, a Chechen rebel leader, claimed responsibility on Wednesday for the twin suicide bombings on the Moscow subway

Chechen rebel leader Doku Umarov is seen in this screenshot taken March 31, 2010. Umarov claimed responsibility for suicide bombings in the Moscow metro that killed at least 39 people, according to a video posted on an unofficial Islamist rebel website on Wednesday.

On Monday, two female suicide bombers killed at least 39 and injured more than 60 in attacks on the Moscow’s subway.

The video was posted just hours after a double bombing killed at least 12 people in Russia’s North Caucasus.

Twelve people, including nine police officers, were killed in two blasts on Wednesday in the town of Kizlyar in the volatile North Caucasus region of Dagestan.

Russian President Dmitry Medvedev Wednesday ordered the government to strengthen security on national transport in response to recent terrorist attacks.

“I have signed a decree today, ordering to build a complex system to guarantee security on transport,” Medvedev told the Security Council as quoted by the Interfax news agency.

According to the decree, priority should be put on public transport such as trains and buses to effectively prevent terrorist attacks.

VietNamNet/Xinhuanet