More than 300 Isis child soldiers have been killed in Mosul, human rights watchdog reports

An estimated 480 Isis fighters have killed since the pro-Government forces launched an offensive on the city

Iraqi forces drive their vehicles in the al-Shura area, south of Mosul (Getty)

More than 300 Isis child soldiers have reportedly been killed in the two weeks since Iraqi government forces and their allies launched an offensive to retake the northern Iraqi city of Mosul currently held by the terror group.

The UK-based Syrian Observatory of Human Rights (SOHR) has been informed the bodies of 40 Isis members killed in Mosul have been taken to the group's de facto capital, Al-Raqqah in the last 24 hours.

The watchdog said the majority of those returned are child fighters known as the "Caliphate Cubs".

At least 480 Isis fighters have been killed since the Battle of Mosul began, SOHR estimates.

The watchdog said on its website: "This will raise the death toll to at least 480 Syrian fighters killed in the ranks of the Islamic State since the start of the battles in the Mosul area, among them more than 300 child soldiers from the ‘lion cubs of the caliphate."

The United Nations has stated at least 232 civilians have been slaughtered by Isis last week alone.

UN rights office spokeswoman Ravina Shamdasani told reporters: "Last Wednesday 232 civilians were reportedly shot to death.

"Of these there were 190 former Iraqi Security Forces officers. These reports have been corroborated to the extent possible."

Pro-government Shia militants have just opened a new front on Mosul with the aim of cutting off Isis' escape route to Syria.