Meanwhile two Assyrian Christians who released by the ISIS said that their captors had pressured them to convert.

According to the Assyrian International News Agency or AINA, a hostage, who spoke using the moniker Robert, said that he and 20 other Assyrians were taken by ISIS militants to Abdul Aziz Mountain after being abducted from their home in Tel Goran in Syria.

There, the group were housed in two small rooms for one night where bearded men came and talked to them.

Robert is one of the 19 Assyrian hostages from Tel Goran who were released by the ISIS on March 1.

"Many bearded people spoke to us, and everyone asked us to convert to Islam," Robert told AINA. "That was their idea that we should convert to Islam."

Robert revealed that they spent the night at the lodging at Abdul Aziz. In the morning, he said, the militants drove them towards the mountains in the direction of Tur Abdin, an Assyrian city in Turkey. They were again placed into rooms, where representatives of the ISIS again asked them to convert to Islam.

After they refused, Robert said, the ISIS militants then told them that they could either pay the jiyza, a poll tax levied on Christians in Arabic countries, or leave the country.

"We said we would pay the jizya but we would not convert," he described the group's response to the militants. The militants then told them that they did not have to pay the jizya yet as the villagers had not taken any armed action against the extremist group.

Robert also said that the militants forbade them to return to their villages as a condition of their release. However, should they insist on returning, the militants threatened to execute them if they were captured again.

According to Assyrian leaders in Hasaka, the number of Assyrians captured by ISIS is as high as 373. There are 150 confirmed captives whose names are known. Various news agencies reporting today raised the number of captured Assyrians to 250.