BAGHDAD (Reuters) - Iraqi security forces and Sunni tribal fighters launched an offensive on Tuesday to dislodge Islamic State militants and secure a supply route in Anbar province, police and tribal sources said.

In other action, bomb attacks across the country killed at least 32 people.

The deadliest was when a car packed with explosives was detonated in the mainly Shi’ite district of New Baghdad in northeastern Baghdad, killing 16 people and wounding 48.

The pro-government offensive tackled Islamic State militants near the western outpost of Haditha in a bid to secure a route to the nearby Ain al-Asad military base.

Haditha and its nearby dam are in one of the few parts of the Sunni Muslim province of Anbar still under the control of Iraq’s Shi’ite-led government forces, who were driven out of the provincial capital Ramadi in May.The offensive started with army and police forces backed by Sunni tribal fighters attacking the Albu Hayat area, 20 km (12 miles) southeast of Haditha, police and tribal sources said.

Militants have used the area to strike the supply route to Ain al-Asad where U.S. Marines are training Iraqi troops.

“We are attacking Daesh from three directions and we will not retreat until retaking Albu Hayat to secure not only Haditha but the supply route to the base”, said Sunni tribal leader Khalid Mijbil al-Nimrawi, using a pejorative term for Islamic State.

Clashes were going on, the sources said, with advancing troops facing heavy fire from the radical Sunni militants who seized swathes of Iraq’s north and west last year.

Meanwhile, at least 32 people were killed in explosions across the country, police and medical sources said.

As well as the bombing in New Baghdad, two others were killed in bomb attacks in Zafaraniya, the predominantly Shi’ite southern district of the capital.

At least six soldiers and policemen were killed in a suicide attack at a checkpoint in the central town of Tarmiya, about 25 km (15 miles) north of Baghdad, police and medical sources said.

Another eight people were killed and 16 wounded when a car bomb went off in a busy commercial street in Mandali, a predominately Kurdish Shi’ite town about 100 km (60 miles) northeast of Baghdad.

No group immediately claimed responsibility for any of the attacks, but Shi’ite areas and government forces are often targeted by Sunni Islamist insurgents the government is struggling to dislodge from large sections of the north and west.

Separately, pictures circulated on social media appeared to show a U.S. drone crashed in a government-controlled desert area near Samawah, about 280 km (170 miles) southeast of Baghdad.

Samawah intelligence chief Brigadier Saad al-Waeli told Reuters that intelligence teams had located a plane body after receiving reports from factory workers.

“Our initial report shows that the plane was an American drone,” he told Reuters.

The Pentagon confirmed an MQ-1 Predator crashed on July 16 while returning to its Iraqi base after a surveillance mission. The drone was unarmed and the Pentagon said the United States was working with Iraqi authorities to recover the aircraft.