A gas station submerged under flood waters from Tropical Storm Harvey is seen in Rose City, Texas Thomson Reuters Reports of price-gouging — including $20 for a gallon of gas and $99 for a case of water — are spiking in areas of Texas most affected by Hurricane Harvey.

The Consumer Protection Division of the Texas attorney general’s office said Thursday that it has received more than 500 complaints of price-gouging.

Most complaints have cited prices ranging from $6 to $8 a gallon for gas.

Texas Attorney General Ken Paxton issued a warning in response to gas stations against any attempt to take advantage of Harvey victims.

"Texas law protects consumers from fraud in Dallas and other parts of Texas outside of the governor’s declared disaster areas," Marc Rylander, communications director for the attorney general’s office, said. “If Dallas consumers are victims of fraud by gas stations, we urge them to contact our agency’s consumer protection hotline so that we can investigate and take appropriate action.”

The agency is looking into nine cases so far but expects more, according to CNN, and gas is far from the only issue.

One convenience store in Houston reportedly charged $20 for a gallon of gas, $8.50 for a water bottle, and $99 for a case of water, the attorney general's office said.

At a Best Western hotel in Robstown, near where Harvey made landfall in Corpus Christi, rooms more than doubled in price after the hurricane, the AG’s office told Austin television station KXAN Thursday. A crew from the station booked a room and was charged $321.89, including taxes, a night. (The normal price is $119 a night.)

Best Western spokeswoman Kelly Dalton said in a statement that the hotel's guests have been reimbursed and the company is severing ties with the Robstown location, describing the price-gouging as "egregious and unethical."

Mark Elliott, president at the nonprofit research firm Mobility, tweeted a receipt from Thursday of a Chevron gas station in Encinal, Texas that appeared to charge $9.99 per gallon for regular fuel.

When Business Insider called the Encinal fuel stop Saturday morning, employee April Garcia said she could not confirm Thursday's price, because she was not working at the time. The store's manager was also not available for comment.

The price at the stop is now $2.99 per gallon, and two stations across the street are priced at $2.45 per gallon, Garcia said on Saturday.

Nationally, the average price of a gallon of regular gasoline reached new highs for 2017, hitting $2.59 on Saturday, up from $2.45 on Thursday, according to the AAA motor club.

Gas prices will likely continue to climb. One of the most important pipelines that ships refined products to the Eastern Seaboard shut down on Thursday, which means that the US Southeast, Mid-Atlantic, and Northeast could see supply disruptions and price increases in coming weeks.

Near Dallas, gas pumps at several stations in areas like Denton, McKinney and Little Elm are experiencing gas shortages, according to CBS News. Most North Texas gas stations are not expected to completely run out of gas, but costs are projected to rise from the shortages. Gas prices in the region have increased nearly 20 cents from before the storm, CBS Dallas-Fort Worth reported.

Price-gouging is not unusual in the wake of large natural disasters, like Harvey.

Areas affected by Hurricanes Katrina and Sandy saw similar reports. During Sandy, some analysts made the case for price-gouging, arguing that laws against it exacerbates shortages and complicates preparedness. Others have called it immoral and "reverse-looting."

Below are reports of Harvey price-gouging in Texas from social media (some are unconfirmed):