WASHINGTON - President Barack Obama and some administration officials have hailed recent military gains against Islamic State in Iraq and Syria, but other US officials and outside experts warn that the U.S.-backed air and ground campaign is far from eradicating the radical Islamic group, and could even backfire.
While Islamic State's defeats in Iraq and Syria have erased its image of invincibility, they threaten to give it greater legitimacy in the eyes of disaffected Sunni Muslims because Shi'ite and Kurdish fighters are a major part of the campaign, some U.S. intelligence officials argue.
A second danger, some US officials said, is that as the group loses ground in the Iraqi city of Falluja and elsewhere, it will turn increasingly to less conventional military tactics and to directing and inspiring more attacks against "soft" targets in Europe, the United States and elsewhere.
One U.S. intelligence official, who spoke on condition of anonymity, warned that in response to losing Falluja and other cities the group likely would turn more to guerrilla tactics to disrupt efforts to restore government services.
"We can expect ISIL to harass local forces that are holding cities it previously controlled, thereby drawing out battles into protracted campaigns," he said.