IS attacked the prison in the town of Hasakeh on Thursday in an attempt to free the prisoners.
At least 300 prisoners and IS members surrendered on Monday, and another 250 surrendered on Tuesday, according to the SDF.
Dozens are still believed to be standing inside the jail with guards being held hostage, and hundreds of children, writes channels.
More than 160 people have been killed in the clashes after the hijacking, among the 114 suspected of being IS fighters, 45 SDF soldiers and several civilians, according to the Syrian Observatory for Human Rights (SOHR).
According to the UN, as many as 45,000 residents of Hasakeh have been driven to flee by the clashes.
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