A man and a teenager captured in separate incidents this past week by Kurdish forces in Syria and identified as U.S. citizens fighting for the Islamic State (IS) terror group are likely not Americans.
A U.S. official, speaking to VOA on condition of anonymity because of the sensitivity of the information, said Thursday that Soulay Noah Su, 16, was not a U.S. citizen.
Fighters with the Syrian Kurdish People's Protection Units (YPG) announced Su's capture Wednesday.
A YPG news release said Su was one of eight IS foreign fighters taken into custody during a special operations mission earlier in the week. YPG officials said the fighters were part of a group planning attacks to slow down the advance of Kurdish forces against the remnants of the terror group's self-proclaimed caliphate.
The U.S. official said another IS fighter captured by Kurdish forces and initially identified as an American was also likely not a U.S. person, despite his alias.
The U.S.-backed Syrian Democratic Forces (SDF) announced the capture Zaid Abed al-Hamid, 35, also known as Abu Zaid al-Ameriki, on Sunday.
An SDF spokesman told VOA that Hamid, along with American Warren Christopher Clark and three other foreign fighters, was captured Dec. 30 during an operation in eastern Deir el-Zour province.
The spokesman said the group had been planning an attack against civilians fleeing the area.
Both Kurdish and U.S. military officials have been bracing for more encounters with foreign fighters as U.S.-backed forces continue to advance into the last 1 percent of IS-held territory in Syria.
U.S. and coalition officials have said about 2,000 IS fighters have been making a last stand for the caliphate since October, many of them foreign fighters who have been described as the terror group's most hardened and loyal followers.
Already, U.S.-backed Syrian forces are holding in excess of 700 foreign fighters, as well as their families. But identifying them is often difficult.
"These people are trained, if they are captured or if they do surrender, to volunteer information that's likely to throw authorities off," said Colin Clarke, a senior research fellow at the Soufan Center, a global security research group in New York.
U.S. counterterrorism officials estimate more than 45,000 fighters from 110 countries, including almost 8,000 Westerners, have flocked to Syria since the start of the conflict, the majority of them ultimately aligning themselves with IS.
250 from U.S.
U.S. officials have also said approximately 250 Americans have traveled or attempted to travel to Syria or Iraq "to fight or otherwise support the conflict."
A study published last year by the George Washington University Program on Extremism identified 73 U.S. persons who had traveled to Syria or Iraq, at least 45 of whom were U.S. citizens or permanent residents.
Twenty-four U.S. persons are believed to have died in Syria, while the whereabouts of another 29 are unknown.
Among those identified in the report was American Clark, who before traveling from the U.S. to Syria sent IS a resume and a cover letter asking to teach English for the group.
Rikar Hussein and Zana Omer contributed to this report.