"Islamic State" (IS) on Saturday released 37 mostly elderly and female Assyrian Christians held hostage since February, two monitoring groups said.

The Assyrian Human Rights Network said in a statement that negotiations were continuing for the release of another 124 members of the ancient Christian minority. More could be released on Monday.

The 27 women and 10 men arrived by bus in Tal Tamr in the Khabur region of Hasaka province in northeastern Syria.

The freed captives are among over 200 people taken hostage by IS when it overran parts of northeastern Syria earlier this year, before being pushed back by Syrian Kurdish fighters and an allied Assyrian Christian militia.

A few of the hostages had been previously been released after negotiations.

It remains unclear how the Christians were released. The Assyrian monitor said the church negotiated their release, but the Britain-based Syrian Observatory for Human Rights said elders from Arab tribes mediated. It is also unclear if a ransom was paid.

Assyrian Christians are an ancient minority mostly scattered around Syria, Iraq and Turkey.

The conflicts in Syria and Iraq has threatened Assyrians and other Christian minorities, forcing many to flee and seek asylum in the West.

Hundreds of thousands were killed or uprooted in the dying days of the Ottoman Empire, leaving their remaining population a fragment of its former self.

The Assyrian diaspora is concentrated in the United States, Germany and Sweden.

cw/rc (AFP, AP, Reuters)