In Istanbul last week, Turkish officials say, militants guided by the Islamic State conducted a coordinated suicide attack on the city’s main airport. In Bangladesh on Friday, a local extremist group that has pledged loyalty to the Islamic State butchered diners in a restaurant. And in Baghdad on Sunday, the Islamic State claimed responsibility for a bombing that killed more than 140 people.
The three deadly attacks are already being viewed by intelligence and law enforcement officials as proof that the Islamic State, the only terrorist group to create a state with borders, is becoming a larger, more sophisticated version of its stateless chief rival, Al Qaeda, as it loses territory under traditional military attack in Iraq and Syria.
Militant volunteers that the Islamic State, also known as ISIS or ISIL, began recruiting, training and sending to the West more than two years ago are now part of mature, clandestine networks, counterterrorism official say. The networks are increasingly responding to calls to accelerate attacks globally as the group suffers setbacks at home, like retreating from Falluja last month after an offensive by Iraqi forces supported by United States airstrikes and advisers.