A bystander injured when a gunman opened fire on a White House security checkpoint remained in serious but stable condition Sunday, the day after U.S. Secret Service officers fatally shot the suspect at the scene.

The Secret Service said the bystander, who has not been identified, suffered a gunshot wound described as not life-threatening. But the agency said it was not yet clear how he was struck during the exchange of gunfire early Saturday evening.

Secret Service Director Sean Curran confirmed no officers were hurt in the incident and directed sympathy toward the wounded civilian.

“Our thoughts are also with the innocent bystander who was wounded during this incident,” Curran said in a statement posted on social media. “The Secret Service is hopeful he will make a full recovery.”

The Metropolitan Police Department identified the dead suspect as Nasire Best, 21, of Dundalk, Maryland. The department said Best began shooting toward the White House checkpoint, and Secret Service personnel returned fire. Best was later pronounced dead at a hospital.

Authorities have released few additional details about the confrontation outside the White House complex. The investigation remains active, and officials did not say whether Best had any known motive or connection to the White House.

The shooting is the latest in a string of security episodes near the White House in recent months, though the Secret Service has not linked any of the incidents.