WASHINGTON -- At least 50 Americans have joined the mix of extremist groups that are fighting to overthrow Syrian President Bashar Assad, and some could try to mount terrorist attacks at home, U.S. intelligence officials said Tuesday.
Intelligence officials say the Syrian civil war has become one of the biggest magnets for Islamic extremists around the globe since CIA-backed militants fought to oust Soviet troops from Afghanistan in the 1980s, a war that ultimately gave rise to Al Qaeda.
James Clapper, the U.S. director of national intelligence, told the House Intelligence Committee on Tuesday that "7,500 or so" foreign fighters are in Syria from 50 countries. Clapper had cited an estimate of 7,000 at a Senate hearing last week.
A U.S. intelligence official told The Times that the total includes at least 50 Americans, a more concrete estimate than authorities have given previously. He declined to be identified because he was not authorized to discuss the figure publicly.
A report in January by the Israel-based Meir Amit Intelligence and Terrorism Information Center estimated that as many as 1,800 people from European countries have also fought in Syria.
CIA Director John Brennan said Tuesday that Al Qaeda is training foreign fighters at camps in Syria and neighboring Iraq.
"We are concerned about the use of Syrian territory by the Al Qaeda organization to recruit individuals ... to use Syria as a launching pad" for attacks on the West, Brennan said.
Clapper said he was particularly concerned about a small cadre of Al Qaeda operatives who have fought in Afghanistan and Pakistan, and who aspire to attack the United States.
"Not only are fighters being drawn to Syria, but so are technologies and techniques that pose particular problems to our defenses," Clapper said.
James B. Comey, the FBI director, has said that counter-terrorism officials are trying to track U.S. veterans of the Syrian war who have returned home.
Prosecutors last year charged U.S. Army veteran Eric Harroun, 31, a native of Phoenix, Ariz., with federal crimes related to fighting with the Nusra Front, a Syrian extremist group linked to Al Qaeda. Harroun pleaded guilty in September to a lesser charge and was released.
Nicole Lynn Mansfield, 33, of Flint, Mich., a convert to Islam who was married to a Saudi man, was killed in May with rebels in northwestern Syria.