Iraqi security forces cross a bridge built by corps of engineers over the Euphrates in Ramadi, December 22, 2015. [Photo/Agencies]

BAGHDAD -- Iraqi security forces on Wednesday continued major offensive for the second day to complete the capture of the city of Ramadi from Islamic State (IS) militants, a provincial security source said.

The anti-terrorism troops, backed by Iraqi and US-led coalition aircraft, engaged in heavy clashes with IS militants in the early morning hours in Albu Diyab area in northern Ramadi, which is located some 110 km north of the Iraqi capital of Baghdad, the source told Xinhua on condition of anonymity.

The troops made a significant advance and recaptured almost half of Albu Diyab area, the source said.

The heavy battles in Albu Diyab left dozens of IS militants dead and wounded, the source said, adding that 16 security members were killed and 12 others injured in a suicide truck bomb attack on a military position in the area.

Furthermore, international warplanes bombarded an IS convoy of 14 vehicles carrying IS militants and ammunition in Albu Diyab area, destroying eight vehicles and killing at least 30 militants aboard, the source added.

Meanwhile, the troops continued their progress from southwestern direction of Ramadi in Houz district a day after they retook control of the adjacent districts of al-Bakr, Dhubbat and Aramel, but their advance was slowed down by IS snipers, dozens of roadside bombs and booby-trapped buildings, the source said.

The slow advance in Ramadi was also attributed to the presence of large number of families who were prevented by IS militants from leaving the city to use them as human shields, the source said, adding that some military vehicles used loudspeakers to instruct the civilians to raise white flags before approaching to the troops.