MEXICO CITY—Anger over gasoline-price increases fueled more protests and looting Thursday, and Mexican officials said the unrest had resulted in the deaths of a policeman and a bystander, the ransacking of 300 stores and arrests of more than 600 people.

The combination of highway, port and terminal blockades and looting this week forced many stores and businesses to close and threatened supplies of basic goods and fuel, the country’s business chambers said.

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