An Assyrian man with a red cross painted on his forehead holds a banner as he walks during a protest of several hundred people in solidarity with Christians abducted in Syria and Iraq.

ISIS militants have killed three Assyrian Christian captives who were among nearly 200 Christians abducted earlier this year in northeastern Syria, two human rights monitoring groups said on Thursday.

The three men were killed late last month but the news emerged this week when a video showing their deaths was released, the Britain-based Syrian Observatory for Human Rights reported.

The Assyrian Human Rights Network said the three men were among 187 Assyrians being held by Islamic State.

Both organizations said they were killed two weeks ago on Eid al-Adha, an Islamic holiday.

ISIS abducted the Assyrians in February during battles with the Syrian Kurdish YPG militia in northeastern Syria.

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