A total of 42 people were killed on Sunday in a suicide truck bombing and clashes with Islamic State (IS) terrorists in Iraq's western province of Anbar, a provincial security source said.In one attack, 15 soldiers and members of allied militias known as Hashd Shaabi, or popular mobilisation, were killed and eight others wounded when a suicide bomber drove an explosive-laden military truck into military positions at the Technical Institute in Saqlawiyah area, the source told Xinhua on condition of anonymity.Meanwhile, four IS militants were killed and seven others injured in artillery shelling by the army on IS positions in the areas of Saqlawiyah and Mukhtar near Fallujah, the source said.Moreover, IS militants pounded a military position in east of Fallujah, killing three soldiers and wounding three others and two Hashd Shaabi militiamen, the source added.Iraqi security forces along with Hashd Shaabi militiamen at dawn advanced toward the provincial capital city of Ramadi, after heavy clashes with the IS militants which left at least 20 extremist militants killed, the source said.