Six people, including the alleged gunman, have been arrested in connection with a shooting Wednesday morning near the entrance to the U.S. Embassy in Beirut, Lebanon, that injured a Lebanese guard, authorities said.
Shots from "small arms" were heard at about 8:34 a.m. local time, the embassy said.
The alleged gunman was shot by the Lebanese Army and suffered non-life-threatening injuries, local authorities said. The suspect, a Syrian national, was arrested and taken to a hospital for treatment, the Lebanese Army said in Arabic on its official social media account.
The Lebanese Army Command said it has also since arrested five more people in connection with the shooting. They include three members of the alleged shooter's family, as well as a Syrian citizen and a Lebanese citizen who are suspected of having a relationship with him, it said.
"The army continues its raid operations in parallel with its follow-up of investigations under the supervision of the competent judiciary," the Lebanese Army Command said in the statement.
A motivation in the shooting is unknown at this time.
The State Department's Diplomatic Security Service was working with Lebanese authorities to determine the motivation, State Department spokesperson Matthew Miller told reporters during a briefing Wednesday.
The alleged shooter was wearing "what appeared to be ISIS insignia," Miller said. "But we are conducting a full investigation with the Lebanese authorities into the actual motivations."
Following the incident, Jake Sullivan, the White House national security adviser, said on "Good Morning America" Wednesday that all American personnel in Lebanon "are safe and accounted for."
A member of the embassy's Lebanese guard force was seriously wounded in the shooting, according to Miller.
The embassy was "secured immediately" following the shooting and remained closed to the public on Wednesday, Miller said. It is expected to reopen on Thursday, U.S. officials said in a security alert.
"Investigations are underway and we are in close contact with host country law enforcement," embassy officials said on social media.
The State Department's preexisting travel advisory for Lebanon advises Americans that "terrorist groups continue plotting possible attacks in Lebanon" and that "terrorists may conduct attacks with little or no warning targeting tourist locations, transportation hubs, markets/shopping malls, and local government facilities."
"The Department of State considers the threat to U.S. government personnel in Beirut sufficiently serious to require them to live and work under strict security," the advisory adds.
ABC News' Shannon K. Crawford contributed to this report.