BEIRUT: Activists and a local leader said the Islamic State group released at least 19 Christians on Sunday who were among the more than 220 people the militants took captive in northeastern Syria last week.

Bashir Saedi, a senior official in the Assyrian Democratic Organization, said the 16 men and three women arrived safely Sunday and were now at the Church of the Virgin Mary in the city of Hassakeh.

The Britain-based Syrian Observatory for Human Rights activist group also reported that 19 Christians had been freed, but put the number at 17 men and two women.

Read: IS jihadists kidnap 90 Christians in Syria: monitor

The discrepancy could not be immediately reconciled. It was not immediately clear why the Islamic State group had freed them, although Saedi said all of the 19 who were released were around 50 years of age or older.

Observatory director Rami Abdurrahman said an Islamic State Shariah court had ordered them released, but the reasoning was unknown.

Also unclear is the fate of the more than 200 other Christian Assyrians who were taken captive by Islamic State fighters last week in sweep through a string of villages along the Khabur River in Syria's northeastern Hassakeh province.

The abductions have added to fears among religious minorities in both Syria and Iraq, who have been repeatedly targeted by the Islamic State group.