WASHINGTON >> The U.S. is trying to determine if a second American fighting with the Islamic State group has been killed in Syria.

State Department spokeswoman Jen Psaki said Wednesday that the U.S. has no independent confirmation of reports of a second American killed while fighting with the militant group. “We’re looking into it,” she said.

NBC cited an anonymous member of the opposition Free Syrian Army as saying two Americans were killed in a battle last week with Islamic State fighters.

The U.S. confirmed the death of one American, Douglas McArthur McCain, who grew up outside Minneapolis in the town of New Hope and most recently lived in San Diego.

A relative, Kenneth McCain, told The Associated Press that the State Department called to tell his family that Douglas McCain had been killed in Syria. “We do not know if he was fighting anyone,” he said.

Investigators were aware that McCain was in Syria to fight with the militant group, said a U.S. official who was not authorized to discuss by name an ongoing investigation and spoke only on condition of anonymity.

Surveillance flights have begun over Syria on the orders of President Barack Obama, a move that could pave the way for airstrikes against the Islamic State group.