"What is important is that the US sends these weapons to only those that cooperate with the Pentagon and this indicates that the US plays a role in arming the ISIL," an Iraqi security source said.

The source noted that the most important advantage of the US-made weapons used by the ISIL is that "these bullets pierce armored vehicles and kill the people inside the vehicle.

He said each of such bullet is worth $2,000, and added, "These weapons have killed many Iraqi military and volunteer forces so far."

The crisis in Iraq escalated after the ISIL militants took control of Mosul in a lightning advance on June 10, which was followed by the fall of Tikrit, located 140 kilometers (87 miles) Northwest of the capital, Baghdad.

Soldiers of the Iraqi army, popular forces and Kurdish Pishmarga troops have been engaged in heavy fighting with the militants on different fronts and have so far been able to push them back in several areas.