ISIS has released 16 more Assyrian Christian hostages following the 25 released on Christmas Day.

The captives were freed in al-Hasakah in Syria, according to reports from the Assyrian Church of the East Relief Organisation (ACERO), a charity working with Assyrian Christians.

A statement on the group's Facebook page broke the story and pleaded for further support.

"The 16 freed hostages, comprising men, women and children, was met and embraced by His Grace Mar Afram Athneil, Bishop of Syria and Chairman of ACERO," read the statement.

"ACERO continues to play a leading role in supporting the released hostages and their families through the generosity of our supporters and partner organizations."

The hostages were among more than 200 people abducted from villages along the Khabour River in northern Syria earlier this year.

ISIS have now released more than 150 captives in total and negotiators are working to secure the release of the roughly one hundred who remain.

The latest release comes after more than two dozen Assyrian Christians were released on Christmas Day. ACERO called the event a "glorious Christmas gift."

A Demand for Action, a campaign group for minorities in the Middle East, previously told Christian Today that the Church is working "day and night to make sure all are returned to their families safely".

In October, militants released a video showing the execution three of the hostages, and threatened to murder those still in captivity if a multi-million dollar ransom was not paid.

Initially, ISIS demanded a ransom fee of around $100,000 per hostage, totalling $23 million. When it became clear that the Assyrian community could not afford it, the amount was lowered to between $12-$14 million.