Walmart says bomb threats caused evacuations at five of its Missouri stores, and the threats have now spread to Kansas with two in Lawrence and one in Leavenworth

No explosives were found at any of the locations.

Company spokesman Dan Fogleman told The Kansas City Star threats were called in Friday evening to stores in Raytown, Gladstone, Jefferson City, Nixa and Ozark.

Fogleman says such threats can happen at any retail establishment, but acknowledged it’s unusual to get so many in one evening.

He says the company is working closely with law enforcement to find out who is responsible.

Two Walmart stores in Tulsa, Okla., received bomb threats on the same day in June, and a 13-year-old boy in Minnesota is suspected of making a threat in April that led to the evacuation of a Walmart in Alabama.