"I can confirm the release of 19 persons (17 men and 2 women) who were captured by the Islamic State in the Khabur region," said Father Emanuel Youkhana, who heads the Christian Aid Program Northern Iraq, CAPNI.
"We pray and hope for the others to be released," he added.
Bashir Saedi, a senior official in the Assyrian Democratic Organization, said all those released were around 50 years of age or older, suggesting that age might have been a factor.
Osama Edward, who heads the Assyrian Human Rights Network, told Vatican Radio that the Christians were released because jizya, an Islamic protection tax levied on non-Muslims, had been paid.
They are now "in the church of the city of Hassakeh," Edward said. The network published photographs on its Facebook page that appeared to show people in Hassakeh greeting the returnees.
The Britain-based Syrian Observatory for Human Rights also reported that an Islamic court had ruled the captives be freed, but it said the reasoning behind the decision was unknown.
On Feb. 23, Islamic State militants raided a cluster of villages along the Khabur River near Syria's northeastern province of Hassakeh and abducted Assyrian Christian residents and other minorities.
There have been conflicting reports about the actual number of the captives still held by the extremists, and their fate remains unclear. The Observatory said there were 220. Other activists said the figure was higher than 260.
Sunni Muslim Arab tribal leaders have been mediating with the extremist militia to secure the captives' release. Many observers believe most captives were taken to Shaddadeh, about 30 miles south of Hassakeh.
The abductions have added to growing fears among religious minorities in the Middle East who have been repeatedly targeted by the Islamic State group, especially in Syria and Iraq. During the militants' campaign in Syria and Iraq over the past year, minorities have been repeatedly targeted and killed, driven from their homes, had their women enslaved and places of worship and cultural artifacts destroyed.
The attacks along the Khabur took place just weeks after video was released of Islamic State beheading 21 Egyptian Christians that it called "crusaders."
At the Vatican, Pope Francis called on everyone to help the people of Syria and Iraq, many of whom are suffering because of their faith.
After praying the Angelus with those gathered in St. Peter's Square March 1, the Pope underlined his dismay over the ongoing "dramatic" events unfolding in the area -- the "violence, kidnappings and oppression to the detriment of Christians and other groups."
He said the church has not forgotten about the minorities and their plight and said Catholics were "praying urgently that the intolerable brutality" they are suffering "may end as soon as possible."
"I ask everyone, according to their means, to work to alleviate the suffering of all those who are afflicted, often just because of their faith," the pontiff said.
Nechirvan Barzani, prime minister of the Kurdistan regional government of Iraq, met Pope Francis at the Vatican March 2 to discuss concerns about Islamic State extremists and the fate of religious and ethnic minorities in the Middle East.
Ra'ed Bahou, Catholic Near East Welfare Association's regional director for Jordan and Iraq, called the release of the first batch of Assyrian Christians "positive," but said the attacks on Christians in Syria were troubling.
"We spoke about the problem of Hassakeh publicly for seven or eight months before this incident. We said that Hassakeh and the nearby villages are all surrounded by Daesh," the Arabic term for Islamic State, Bahou told CNS. "Despite the warning, nothing happened to protect them."
A prominent Syrian Christian, Bassam Ishak, president of the Syriac National Council of Syria, added that he raised concerns earlier about the Islamic State presence in the Hassakeh region as well in Washington, but no real measures were taken.
"If you go back to July 22, 2014, we warned publicly that Daesh will enter the Ninevah Valley, and it happened 14 days later," Bahou said, referring to massive attacks on Iraqi Christian villages last summer that sent thousands fleeing for safety to northern Iraq and neighboring countries.
"When there is warning, the international community must act," Bahou said.
He said he believed with the announcement of a military campaign by Iraqi troops and the U.S.-led coalition to retake Mosul, Iraq, this spring, the militants will try to take over more territory.
"They want to take more lands because they will lose Mosul and go back to Syria. They want more lands because that is the only way they can survive," Bahou said. "We (Christians) will have more pressure in the future."
"It's been a cleansing of the Iraqi Christians. I think it will be a domino effect. It's now happening in Syria. It's happening in Egypt, in Lebanon," Bahou added.
"Thank God we have stability in Jordan, and we hope it will continue. But we are losing Christians in our region," he said.