As Islamic State loses territory in the grinding war in the Middle East, it is turning to less elaborate but lethal direct attacks on civilian targets such as this past week’s series of deadly suicide bombings in Iraq.

In three straight days of bombings in Baghdad starting on Wednesday, the group killed more than 100 people. In the wake of the terror attacks in Paris in November and Brussels in March, Western and regional officials said they are seeing more signs the militants are morphing back into a guerrilla-style insurgency that relies increasingly on suicide attacks.

Iraq’s Interior Ministry spokesman Brig. Gen. Saad Maan said the latest terror attacks in Iraq stem from Islamic State’s need to make an impact away from the battlefield.

“It is well known that whenever there is a military victory against [Islamic State, they] resort to this criminal, cowardly act by using car bombs or suicide bombers to kill innocent people,” Gen. Maan said Wednesday after three suicide bombings killed at least 88 people. Another suicide attack on Friday at a Baghdad coffee shop killed at least 13 more.

Islamic State remains a formidable enemy in both Iraq and Syria despite nearly 12,000 U.S.-led strikes on the group since an air campaign against it began in 2014. The radical Sunni fighters retain a vast expanse of territory in Syria and Iraq from where they can train fighters, plot attacks on nearby and distant targets, and generate income, most notably from oil.