A good read on the terrorist's "He said the Islamic Movement of Uzbekistan and one of its splinter groups, the Islamic Jihad Union, both have recruited Chechen, Turks and other non-Arab Muslims to fight with them against U.S. forces in Afghanistan. According to Kohlmann, both of these groups are based in the Waziristan tribal area of Pakistan, "and these groups can be just as radical as anything al-Qaeda puts out."

"They have a strong animus against the United States," Kohlmann said.

But he cautioned against making any assumption at this point that the bombing suspects were recruited and/or trained by foreign terror organizations.

"What happened (in Boston) is within the capability of two relatively sophisticated, homegrown individuals," Kohlmann said. "These two people seem to have come out of nowhere."

David Schanzer, a terrorism expert at Duke University, said the attack appeared to be "homegrown" and that the suspects appear unsophisticated and without ties to or training from international terrorist groups.

"The fact that they needed to rob an ATM to get money (suggests) they didn't get large amount of outside funding. They had no escape plan to leave the country," Schanzer said. "These are hallmarks of people who are not particularly sophisticated. I don't see this as a highly planned plot. They seemed to be making this up as they go along."

Several links have been identified between Chechen guerrillas and al-Qaeda, according to an analysis by the Council on Foreign Relations.

Despite the two suspects' apparent affinity for the Chechen cause, anti-separatist Chechen leader Ramzan Kadyrov said there was no link between his country and Tamerlan and Dzhokhar Tsarnaev, the two brothers suspected of the Boston bombings.

"We don't know the Tsarnaevs, they did not live in Chechnya. They lived and studied in America," Kadyrov said Friday. "It has become habitual, everything that is happening in the world is connected to Chechens. Blame the Chechens."

Kohlmann sent a post on his Twitter feed Friday that the official arm of the Chechen mujahedin has denied any connection between them and the Boston suspects.

Ruslan Tsarni of Montgomery Village, Md., the uncle of the two brothers, said the family was ethnic Chechen.

Author Kimberly Marten, who researched Chechnya for her recent book, Warlords Strong-Arm Brokers in Weak States, cautioned Friday against concluding that the Boston attack was an act of terror.

"We shouldn't assume... there's a political motive behind the bombing," said Marten, who's a political science professor at Barnard College in New York City and director of Columbia University's Harriman Institute.

Most of the Chechens' acts have come in Chechnya, Russia or neighboring republics.

Among the most shocking acts of violence was an attack in the neighboring republic of North Ossetia in 2004, where militants seized a school and, in the three-day siege that followed, more than 300 were killed, most of them children.

The attack was ordered by Chechen separatist leader Shamil Basayev, who was himself killed in a 2006 bombing believed to have been conducted by Russian internal security forces.

Militants from Chechnya and other restive regions have targeted Moscow and other areas with bombings and hostage-takings for more than 20 years. The republic is predominantly Muslim and has waged two wars with Russian security forces since the demise of the Soviet Union in 1991.

p******** Vladimir Putin has often stressed that al-Qaeda is linked with Chechen fighters. According to the Council on Foreign Relations analysis, a Chechen warlord is said to have met with Osama bin Laden while both were fighting against the Soviet occupation of Afghanistan from 1979-89.

Authorities have also found links between Chechen separatists and other Islamist terrorist groups. The U.S. Justice Department said in a 2004 report that Zacharias Moussaoui, who was convicted for his role in the 9/11 attacks, had previously sought to recruit at least one man to fight in Chechnya. Intelligence officials in France had warned the FBI of Moussaoui's connection to the Chechen fighters.

An online jihadist, "Abu Sulaiman al-Nasser," boasted Friday that the Tsarnaev brothers "made the streets of America just like the streets of Afghanistan."

Violence dates back to the years after World War II when the Soviet leader Josef Stalin crushed a revolt there during the Nazi invasion and in 1944 deported the entire Chechen population to Siberia and Kazakhstan. They were allowed to return to their homeland in 1957.

Shortly after the Soviet Union's collapse, Chechnya declared independence from Russia, a move that eventually led to war from 1994-1996 when tens of thousands died and Russian regained control of the republic.

The Tsarnaev family reportedly fled Chechnya for nearby Kazakhstan and, later, the United States.

Fighting broke out in Chechnya again in 2000 when Russian forces destroyed much of the republic's capital city of Grozny in a bid to crush resistance. With the killing of key militant leaders, the separatist movement has been quelled, although violence in the region continues.

Chechen militants have committed sporadic large-scale attacks in Russia since the 1990s. In March 2010, Chechen terrorists claimed responsibility for bombings on the Moscow subway system that killed more than 40 people. In June 2010, the State Department added Chechen rebel Doku Umarov, who claimed responsibility for the March subway attack, to its terrorist list and froze his assets.

A 2008 report by the Congressional Research Service said in 2007 Russian security forces ran 850 sweeps through Chechnya that involved surrounding entire villages and searching every house. "Critics of the operations allege that the troops frequently engage in pillaging and gratuitous violence and are responsible for kidnappings for ransom and 'disappearances' of civilians,' " the report said.

Of the region's almost 1.3 million residents, ethnic Chechens make up about 95%, according to Russian government statistics. The rest are a combination of ethnic Russians and other ethnic groups from nearby countries and regions"