The Islamic State group launched a coordinated assault Sunday on a natural gas plant north of Baghdad that killed at least 14 people, while a string of other bomb attacks in or close to the capital killed 15 others, Iraqi officials said.

The dawn attack on the gas plant began with a suicide car bombing at the facility's main gate in the town of Taji, about 20 kilometers (12 miles) north of Baghdad. Several suicide bombers and militants then broke into the plant and clashed with security forces. The dead included six civilians and eight security forces; 27 troops were wounded.

The IS-affiliated Aamaq news agency credited a group of "caliphate soldiers" for the attack.

Closed-circuit television images showed as an explosion hit inside the facility. As flames engulfed the facility and nearby palm trees, pedestrians were seen running for cover. A crowd gathered to watch as thick black smoke rose above the plant, sections of which were left in ruins. The top of one of the gas-processing units was blown off.

In a statement, Deputy Oil Minister Hamid Younis said firefighters managed to control and extinguish the fire. He said technicians were examining the damage. Hours after the attack, passers-by inspecting the damage posed for cell phone photos in front of the ruined complex.

Elsewhere, four separate bomb attacks left another 15 people dead and 46 wounded in the fifth-straight day of IS-claimed attacks in and around the Iraqi capital. Since Wednesday, more than 140 people have been killed in a spate of bombings in Baghdad and elsewhere.

The wave of attacks comes as Iraqi ground forces have achieved a number of key territorial victories against the extremist group.

Brett McGurk, the Obama administration's diplomatic point man in the international fight against the Islamic State group, told journalists in Jordan that the tide was turning against extremists.

"This perverse caliphate is shrinking," said McGurk, a presidential envoy to the 66-member anti-IS coalition.

In the past month, IS has lost a swath of key territory along a supply route in Iraq's vast western Anbar province that the extremists had used to ferry fighters and supplies between Iraq and Syria. But after losing territory along the Euphrates River valley, that line has been cut, according to Iraqi and coalition officials.

As the Islamic State militants are pushed back along front lines, the group is increasingly turning to insurgency-style terrorist attacks to detract from their losses, the officials said.

However, despite battlefield successes against IS, Iraq's political leadership is in disarray as a deepening political crisis has gridlocked government. Parliament has not met for more than two weeks after supporters of influential Shiite cleric Muqtada al-Sadr stormed Baghdad's highly fortified Green Zone. The breach followed repeated delays to government reform legislation that lawmakers claimed would fight Iraq's entrenched corruption.

"It's possible that some of the political unrest in Baghdad has led (the Islamic State group) to think that they can somehow stir up more chaos than usual," said Nathaniel Rabkin, managing editor of Inside Iraqi Politics, a political risk assessment newsletter.

"ISIS hopes that somehow if they just keep up the pressure, the Iraqi government will at best collapse or at least become incapable of pursuing a cohesive approach" to fighting the extremists , Rabkin said, using an alternative acronym for IS.

While the U.S.-led coalition acknowledges the planning phase of Iraqi military operations against the Islamic State group has been slowed by political unrest, Rabkin says there is no evidence the IS terrorist attacks have had a direct impact on the military campaign against the extremists.

Besides the assault on the gas plant, Sunday's attacks included a car bomb at a shopping area in the town of Latifiyah, about 20 miles (30 kilometers) south of the capital, that killed seven people, including two soldier, officials said. Eighteen people were wounded in the attack, four of whom were soldiers.

Elsewhere in Baghdad, three separate bomb attacks targeted commercial areas, killing at least eight civilians and wounding 28 others, police said. At total of 29 people were killed in the day's violence.

Medical officials confirmed the casualty figures. All officials spoke on condition of anonymity as they were not authorized to release information.

IS extremists still control significant areas in northern and western Iraq, including the country's second-largest city of Mosul. The group declared an Islamic caliphate on the territory it holds in Iraq and Syria and at the height of its power was estimated to hold nearly a third of Iraqi territory. Iraq's Prime Minister says the group's hold has since shrunk to 14 percent.