BAGHDAD - An air strike by US-led coalition aircraft targeting a position of the terrorist Islamic State (IS) group in Iraq's western province of Anbar on Sunday killed 12 IS militants, a security source said.

The international warplanes bombarded a suspected car bomb making factory in the IS-held town of Heet, some 160 km west of the Iraqi capital of Baghdad, destroying the target and leaving at least 12 IS militants killed, the source told Xinhua, citing intelligence report.

Iraqi security forces and allied paramilitary units, known as Hashd Shaabi, have been fighting for months to retake control of key cities and towns in Iraq's largest province from IS militants, who have seized most of Anbar and tried to advance toward Baghdad.

In Salahudin province, two policemen were killed in a clash with IS militants during a security operation in Himreen mountainous area aimed to rescue 10 family members who escaped the IS-held town of Hawijah and were chased by extremist militants, a provincial security source told Xinhua on condition of anonymity.

The troops managed to rescue five family members, including an eight-year-old child, while the other five have not been found yet by the troops who continued their operation in the rugged area, the source said.

During the past months, the IS militants have been preventing civilians from leaving their homes in IS-held cities and towns in order to use them as human shields against possible attacks. However, many managed to escape despite the IS threat to execute them, but many others failed.

Iraq has been witnessing some of the worst violence in years.

Terrorism and violence have left at least 12,282 civilians dead and 23,126 others injured in 2014, making it the deadliest year since the flareup of sectarian violence in 2006-2007, according to a recent United Nations report.