In a video message posted on a Chechen rebel website, militant leader Doku Umarov said his group was behind Monday's double suicide bombings on the Moscow Metro, BBC reported on Wednesday.
The rebel, who styles himself as the Emir of the Caucasus Emirate, said attacks on Russian soil would continue.
He said that he had personally ordered the attacks to avenge the killings of "poor Chechens" by Russian security forces in February and warned Russia to prepare for more.
He said the civilians were "massacred by Russian occupiers" near the town of Arshty Feb 11 as they were gathering wild garlic to feed their families.
The message came as Russia buried the first victims of Monday's attacks.
Russian investigators have said they believe two female suicide bombers were linked to militants in the North Caucasus.
Prime Minister Vladimir Putin has called on the security forces to "scrape from the sewers" those responsible.
Deccan Herald is on WhatsApp Channels| Join now for Breaking News & Editor's Picks