Authorities say they've received at least one report of looting in the aftermath of the catastrophic fertilizer plant explosion that's killed as many as 15 people and injured more than 160.

Waco police Sgt. W. Patrick Swanton says there was an "isolated incident" of looting in a neighborhood near the West Fertilizer Co.

He says the report is "a significant concern to us." He described the areas around the plant as "very secure" with a heavy presence by law enforcement.

Swanton previously said at least one person suspected of being a looter was seen running from a damaged home.

Responders are concentrating on a "hard, gut-wrenching job" and Swanton says despite looting reports, "West has seen a tremendous outpouring of support."