In a statement issued on Sunday, the Command of the Mujahideen of the Caucasus Emirate said the terror group had never trained, met or made contact with Tamerlan Tsarnaev, one of the two brothers involved in last week's terror attack.
"The Caucasian Mujahideen are not fighting against the United States of America. We are at war with Russia, which is not only responsible for the occupation of the Caucasus, but also for heinous crimes against Muslims," it adds.
The younger brother, Dzhokhar Tsarnaev, was charged Monday with using a weapon of mass destruction to kill three people and injure more than 200 during the Boston attack.
The elder Tsarnaev was killed in a violent shootout with federal agents and local police last Friday. Hours later, the younger brother was placed under arrest after a tense standoff with police.
The White House announced on Monday the younger Tsarnaev would not be held as an enemy combatant and would stand trial in federal court.
FBI agents questioned the older Tsarnaev brother in 2011 after his visit to Russia raised a number of red flags among intelligence officials in the country.
During his six-month trip, reportedly to visit family and renew his Russian passport, Tamerlan Tsarnaev also spent time in Dagestan.
Since the attacks, federal investigators and intelligence officials have been attempting to piece together the details of that trip, particularly the time spent in Dagestan, to see if he linked up with terror groups in the area.
Michael Sheehan, DOD's chief of special operations and low-intensity conflict, warned Congress that militant leaders are seeking recruits in the United States, the United Kingdom and elsewhere in the West to make up the terror group's "second generation" of Islamic militants.
Defense Department officials are currently exploring the "phenomena" of radical Islamic groups going after first and second-generation American and European citizens who "maybe more receptive to becoming operationalized," Sheehan told lawmakers earlier this month.
But extremist leaders in the south Russian state called said any links between the older Tsarnaev and the group was simply "Russian propaganda" designed to put the organization in Washington's cross hairs.
"Even in respect to the enemy state of Russia, which is fighting the Caucasus Emirate, there is an order . . . which prohibits strikes on civilian targets," the group says, noting the Boston attack would have violated that order.
"In this regard, the Command of the Mujahideen of the Province of Dagestan urges the media, primarily the American, to halt speculations and promotion of Russian propaganda," they added.
Established in 2007, the group with loose ties to al Qaeda is battling Russian forces in an attempt to establish a Muslim state in Chechnya.
Since then, Islamist fighters from Dagestan, Chechnya and elsewhere in the South Cauacus states have made their way onto the battlefields of Iraq and Afghanistan to fight U.S. and allied forces there.