Earlier on Monday at least 300 militants surrendered handed as the Syrian Democratic Forces (SDF) commandos moved into the facility in the north-eastern city of Hasaka.

However, reports said that dozens of militants are still thought to be holed up inside the prison holding several guards and several hundred children as hostages. 

The prison had been attacked and seized by the Islamic State last Thursday when they tried to carry out a mass breakout. 

According to reports so far in the ensuing fighting more than 160 people have so far been killed, including 114 suspected militants and 45 SDF personnel.

Before the take over last week the prison held some 4,000 men and boys detained by the SDF, a US-backed militia alliance that controls much of northern and eastern Syria.