By Mark Hosenball
WASHINGTON, Oct 14 (Reuters) - U.S. government agencies are investigating claims that an American fighting with the Islamic State militant group died recently in the besieged Syrian border town of Kobani.
U.S. officials said law enforcement and intelligence agencies were trying to confirm Internet postings by Islamic State militants which last weekend reported the "martyrdom" of a fighter known as Abu Muhammad al-Amriki.
The nom-de-guerre indicated that the man considered himself an American.
In a video posted on YouTube in February, a bearded man believed by U.S. authorities to be the same individual is seen speaking English with a heavy foreign accent.
The man in the video said he had lived in the United States for about 10 years before traveling to Syria to join Islamist militants. It is unclear if he was a U.S. citizen.
U.S. officials say at least a handful of Americans - including a Michigan woman and men from Florida and Minnesota - have died in Syrian fighting over the last two years. One of the men, Moner Mohammed Abusalha, blew himself up in a suicide bombing earlier this year, they say.
U.S. and European authorities are deeply concerned about Western foreign fighters in Syria who might return to their home countries to carry out attacks.
On Tuesday, presidential counter-terrorism advisor Lisa Monaco discussed this threat with New York Mayor Bill De Blasio and Police Commissioner William Bratton, according to a White House announcement.
Precise circumstances of the latest reported American death in Syria were unclear. Flashpoint Partners, a firm which monitors jihadist Web traffic, said Abu Muhammad was reported to have been killed during recent clashes in Kobani, the Kurdish town in Syria on the Turkish border that has been under attack for days by Islamic State fighters.
Flashpoint said some message traffic suggested that Abu Muhammad was wounded, not killed.
In the video posted last winter, the man calling himself Abu Muhammad said when he originally arrived in Syria he was an al Qaeda affiliate but he had defected to Islamic State after the groups clashed. (Reporting By Mark Hosenball; Editing by David Story and Gunna Dickson)