Islamic State executes 7 of its fighters after they tried to run away from Mosul

​Baghdad: Jihadist group Islamic State (IS) executed at least seven of its militants who tried to flee the embattled city of Mosul, local news website Ara News reported, citing local activists.

"The seven IS fighters were executed by a firing squad after they were arrested at the Syrian border on Sunday and charged with high treason," Ara News said on Monday.

Local activists reported that the militants' actual offence was desertion.

"Those fighters had evacuated their posts in Mosul city without permission, heading to the Syrian border," media activist Abdullah al-Malla told Ara News.

Eyewitnesses said that the executed jihadists had fled from battles raging in Iraq's Nineveh governorate where a major military offensive is underway to re-take Mosul from IS and push the group out of Iraq.

Thousands of fighters, including Iraqi federal troops and Kurdish peshmerga, are taking part in the assault being backed by a US-led coalition.

IS captured Mosul in June 2014 and declared it the capital of its Islamic 'caliphate' stretching across territories it seized in Iraq and Syria during an offensive.

US military officials believe 3,000 to 5,000 IS fighters are defending Mosul inside the city and 1,000 to 2,000 are on the outskirts.

There is deep concern for an estimated 1.2 million civilians still believed to be in the city.