SAN DIEGO -- Retailers in San Diego who increase the price of certain products like masks and hand sanitizer amid the swine flu state of emergency may be breaking the law, the city attorney announced Monday.

It is illegal for businesses to increase prices of essential goods and services by more than 10 percent unless they can prove it was due to an increase in their supplier's price.

"Price gouging during a state of emergency is a violation of the law and will not be tolerated," San Diego City Attorney Jan Goldsmith said. "Our office will carefully evaluate and won't hesitate to prosecute such cases that may arise in the city of San Diego."

That message was echoed by District Attorney Bonnie Dumanis.

"While health officials continue to stress there is no need for panic, retailers who seek to take advantage of the situation by increasing prices for certain products need to know they may be breaking the law," Dumanis said. "Consumers should also know their rights and legal protections in place as they shop for items such as masks and hand sanitizer." Consumers can report price gouging by calling the city attorney's consumer and environmental protection unit hotline at 619-533-5600.