The Islamic State of Iraq and the Levant (ISIL) has released 22 Assyrian Christians who were abducted along with over 200 others in Syria last February, Al Jazeera has learnt.

The Assyrian Federation of Sweden, which has been monitoring the case, reported on Tuesday that the captives were released near Hasakah city in northeastern Syria.

Afram Yakoub, the chairman of the federation, said they were sent by ISIL on a bus and picked up by a group of Assyrians on a highway outside Hasakah.

He said 14 of the released were women.

"Most of those released are elderly and have health issues," Yakoub told Al Jazeera.

"Negotiations between Assyrian leaders and Sunni leaders who have pledged allegiance to ISIL have been taking place, and following an agreement they were released. No ransom was paid to ISIL through any negotiations."

The abductions were reported after ISIL fighters seized two Assyrian villages from Kurdish forces along the Khabur River in the province of Hasakah in February.

Pressure to convert

Yakoub added that the captives had not been physically harmed.

"ISIL seperated the men from the women and children, and crammed them all into very small rooms. They were fed disgusting and inedible food," he said.

"During their captivity, ISIL tried to convince them to convert to Islam."

Yakoub said negotiations are ongoing to free more than 200 other captured Assyrians whose location has still not been determined.

"All we know is that they are in Syria, in either Hasakah province or Raqqa province," he said, adding that only 45 Assyrians have been released since the mass abductions.

"Since February we have lost all hope, but today this move brought back to us some hope," he said.

Last week, ISIL abducted at least 230 people, including 60 Christians, after seizing the strategic town of Qaryatain in Homs province, the UK-based Syrian Observatory for Human Rights reported.

ISIL seized the Christians from a church in Qaryatain, which was captured by the group after heavy fighting with the Syrian army.

Qaryatain is near a road linking the ancient city of Palmyra to the Qalamoun mountains, along the border with Lebanon.

During ISIL's offensive to seize territory in Syria, hundreds of people from different religious sects have been abducted or killed.