Islamic State militants rarely miss a chance, however tenuous the link, to claim at least partial credit for apparent terrorist attacks on U.S soil, from the June's deadly mass shooting at a gay nightclub in Orlando, Florida, to the stabbing of nine people in a Minnesota shopping mall Saturday.

They're eager to precisely because they apparently haven't carried out carefully planned attacks here and because, in terrorism circles, your influence is often ranked by numbers of attacks, terrorism experts say.

"If they can't claim attacks, they can't get recruits and can't raise money," according to Dan Byman, a senior fellow in the Center for Middle East Policy at the Brookings Institution in Washington, D.C.

Some militant groups, including al-Qaida, are more reluctant about associating themselves with attackers unless it is clear they adhere to their core beliefs, Byman said. But Islamic State appears to be less discriminating, requiring little information about attackers, said Karen Greenberg, the director of the Fordham Law School's Center on National Security in New York.

"If they find out the person is Muslim — that alone might be enough for them to claim credit," she said.

Other groups may also pause to gauge whether an attack crossed certain lines of brutality, something that Byman said isn't an issue for IS, whose calling card has been extreme violence.

An Islamic State-run news agency claimed on Sunday that the attack at the Crossroads Center mall in St. Cloud, Minnesota, was a "soldier of the Islamic State: who had heeded calls for attacks in nations in the U.S.-led anti-IS coalition. But authorities say there's no sign yet that the attacker, identified by his father as Somali immigrant Dahir Adan, was radicalized or communicated with any terrorist group.

The speed with which IS weighed in may also say something about a competition for recruits between the Middle East-based IS and the east Africa-based militant group al-Shabab, which has recruited Somali-Americans from Minnesota with some success in recent years, but has seen allegiances switching increasingly from al-Shabab to Islamic State, Greenberg said.

Islamic State has claimed at least partial credit for at least four attacks in the United States over the past two years, according to the Center on National Security. Aside from Minnesota, the others are:

— June 12 attack on the Orlando gay nightclub Pulse by an American-born Muslim Omar Mateen. IS claimed partial credit via one of its news services the day after he fatally shot 49 people, according to the center. During the attack, Mateen offered allegiance to Islamic State during a 911 call.

— Dec. 2, 2015, attack in San Bernardino, California, that left 14 people dead. The center said IS claimed credit days after news reports said alleged attackers Syed Rizwan Farook and Tashfeen Malik had pledged allegiance to Islamic States.

— May 3, 2015, attack by two gunmen in Garland, Texas, during an exhibit of images of the Prophet Muhammad. IS claimed responsibility on Twitter and through its news services.


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