Looters attacked supermarkets in several Argentine cities Friday in the latest challenge to President Cristina Kirchner, who is struggling to revive a weak economy and maintain her control over the ruling Peronist Party. What started with the ouster Thursday afternoon of a supermarket in the Patagonian resort town of Bariloche quickly spread to other parts of the country, with thousands of looters attacking supermarkets and shops in the cities of Rosario, Campana and Zárate. In the central city Rosario, two people were killed during the incidents and 137 people arrested.