BAGHDAD — 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 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 Islamic State-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 Islamic State-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 that is also known as ISIS or ISIL.

Brett McGurk, the Obama administration’s diplomatic point man in the international fight against the ISIS, 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-Islamic State coalition.

In the past month, ISIS 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 ISIS 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 ISIS, Iraq’s political leadership is in disarray as a deepening political crisis has gridlocked government. Parliament has not met for more than two weeks.