"ISIS (is) returning to suicide bombings ... it relies on suicide attacks for very spectacular headlines and it's not hard to have a person strap on a suicide vest and walk into a market and blow himself up," special envoy Brett McGurk said.
"Now this perverse caliphate is shrinking so they are very much on the defensive," he added. "Their territory is shrinking, and they are now doing these barbaric suicide attacks against the civilian populations."
- On Wednesday, several bombs struck various Baghdad neighborhoods, killing over 90 people.
- On Thursday, two suicide bombers attacked a police station in Baghdad, killing three officers.
- On Friday, three ISIS gunmen opened fire on a coffee shop in Balad, killing 13 people.
- On Sunday, a car bomb explodes near shops in Latifiya, killing two people.
- And on Sunday, two bombs strike a gas plant in Taji, killing 10 people.
Experts have blamed the violence in part on a security vacuum they say has opened once again in Iraq as the country faces renewed political turmoil.
Prime Minister Haider al-Abadi is struggling to firm up a government capable of battling ISIS and, at the same time, address the country's long-standing economic and political wounds from years of war.
Terrorists have taken advantage of this vacuum to launch a fresh wave of deadly attacks, experts said.
Signs of weakness
But ISIS has lost a significant amount of territory
since declaring its so-called Islamic caliphate over swaths of Iraq and Syria in June 2014.
A U.S.-led coalition has been pummeling ISIS targets with airstrikes. Two major Iraqi cities that had fallen to ISIS -- Tikrit and Ramadi -- have been reclaimed.
Tikrit is somewhat of a success story after ISIS occupation, McGurk said. He said according to U.N. estimates, 95% of the city's population has returned home. McGurk said the situation was far from perfect, but on the right track.
Iraq's government also has been planning a major offensive to recapture the northern city of Mosul, the largest city under ISIS control.
The coalition is launching airstrikes in Mosul almost daily, McGurk said. He said ISIS' situation in the area has gotten so bad, it's had to cut the pay of its fighters in the area by half.
Analysts say the loss of land has prompted the terror group to change its tactics, activating sleeper cells and striking soft targets.
"ISIS has receded somewhat militarily; they don't have a ... standing army to hold territory," political risk analyst Kirk Sowell told CNN
last week. "But what they're good at, unfortunately, is these terrorist attacks against soft targets."
And there are signs ISIS is worried about the future. Last week. U.S. military officials said the terror group had declared a state of emergency
in its self-declared capital of Raqqa -- apparently expecting that the city was about to come under siege.