Mexico City ? A human head washes up on an Acapulco beach. Protesters hassle visitors at makeshift checkpoints in the colonial city of Oaxaca. And in Mexico City, leftist demonstrators turn the tourist draws of Reforma Avenue and the Zocalo plaza into sprawling, ragtag protest camps.

Growing political unrest and drug violence are making foreigners think twice about visiting Mexico, where the $11.8 billion tourism industry is the country’s third-largest legal source of income, after oil and remittances from migrants in the U.S.

Mexico has been struggling since last fall, when Hurricane Wilma hit the country’s biggest tourism moneymaker, Cancun.

No tourists have been reported hurt in Mexico City, Oaxaca or Acapulco, but hotels are being hit by cancellations of thousands of reservations.

In Mexico City alone, hotels, restaurants and stores are losing $23 million a day, according to the city’s Commerce, Services and Tourism Chamber. Some businesses have threatened to stop paying taxes unless the government cracks down on the demonstrations.

Protesters in Oaxaca, claiming fraud in the state gubernatorial race, have taken over the picturesque downtown to pressure Gov. Ulises Ruiz to step down. They forced the cancellation of an ethnic festival, and tourists must pass through checkpoints to reach the arch-ringed main plaza.

Protesters want to use the unrest to “force the population that relies on tourism to pressure the government,” said Jose Escobar, head of the Oaxaca employers’ federation.

In the Pacific resort of Acapulco, drug gangs are battling for control of lucrative smuggling and sales routes. Human heads have been dumped in front of government offices and in the glittering resort’s bay. There have been gun battles on the streets.

In Mexico City, supporters of Andres Manuel Lopez Obrador have taken over streets to press election officials for a re-count in the disputed July 2 presidential elections.

And tourism officials say things could get worse.

“If this goes on for a week or 10 days more, some hotels are going to be in a desperate situation,” said Carlos Mackinlay, director of Mexico City tourism.

Double-decker buses no longer tour the tree-lined Reforma, which connects the city’s Chapultepec Park to the historic center but is now closed to traffic. Museums, restaurants and hotels stand largely empty.

Things aren’t likely to improve soon.

“This is only the first step,” said protester Fernando Martinez, helping block a downtown office building. “Next, we’re going after the airports.”