The U.S. Justice Department is deepening its monitoring of Americans fighting in Syria due to fears about the potential domestic terrorism threat they pose.
The department has appointed a special prosecutor, Stephen Ponticello, to investigate individuals, including U.S. nationals, who travel to Syria to join the opposition movement fighting to overthrow the Bashar Assad regime, Reuters reported on Thursday.
Additionally, the FBI has established a special unit to learn the identities of U.S. citizens who have traveled or are traveling to the Arab country to join the revolution.
Many of the international fighters that join the Syrian opposition link up with its more extremist militias, particularly Jabhat al-Nusra and the Islamic State of Iraq and Syria. The two militias have current or past ties to al-Qaida, and the latter group has made a particular name for itself with its brutal killings of captured fighters and terrorist attacks on civilian targets.
U.S. security officials say the specter of radicalized U.S. citizens returning from Syria intent on launching domestic attacks is one of the biggest terrorism threats facing the country.
John Carlin, who heads the Justice Department's national security division, on Thursday said Ponticello will collaborate with counterparts in Europe and other parts of the globe to investigate foreign fighters in Syria. "We want to make sure that individuals in the counterterrorism section and the U.S. Attorneys throughout the country are focused on this threat," he said during a think-tank event in Washington.
In the past, travel by Americans "to locations such as Yemen, Pakistan, Somalia, have been of particular concern due to the terrorist groups operating in those regions," FBI spokesman Paul Bresson said. Now, however, "Syria has emerged as an area of great concern due to the ongoing conflict and extremist activity in the region."
U.S. State Department spokeswoman Jen Psaki on Wednesday said some 9,000 international combatants are estimated to have traveled to Syria since the civil war broke out in 2011. U.S. officials estimate that several dozen U.S. citizens or residents have joined the revolution.