TIJUANA, Mexico (AP) " Demonstrators have taken control of Mexican border crossings with the U.S. several times in the past month to oppose Mexican gasoline price hikes in an unusual, if not unprecedented, show of protest.
Here are some questions and answers about the protests and their impact:
WHAT IS HAPPENING?
Protesters in Mexico who are upset about gas prices have occupied inspection lanes several times this month for vehicles entering from the U.S.
At the request of the Mexican government, U.S. authorities have been blocking vehicles from entering Mexico.
In other places, Mexican authorities have abandoned their positions, letting protesters wave people through without being stopped.
On Sunday, U.S. authorities blocked southbound vehicle traffic for 5 hours at the San Ysidro port of entry between Tijuana and San Diego, the busiest crossing on the border. The California Highway Patrol directed motorists several miles east to the Otay Mesa crossing.
It was the third straight weekend that freeway access into Mexico has been blocked at San Ysidro. In Nogales, Arizona, motorists were diverted to another crossing on Sunday for the second time this month.
"I don't know of any precedent for protesters taking over ports of entry in either direction," said David Shirk, associate professor of political science and international relations at the University of San Diego. "It obviously underscores the public sentiment in Mexico today, which is extremely anti-government."
Travelers entering the U.S. from Mexico and pedestrians going to Mexico have not been affected.
WHAT DO THE PROTESTERS WANT?
Demonstrators oppose nationwide gas price increases of up to 20 percent at the country's state-owned oil monopoly.
While gas prices were the catalyst, demonstrators are airing a long list of grievances against President Enrique Pena Nieto and other authorities.
In Tijuana, grievances include a weakened peso, a federal sales-tax increase that took effect three years ago, and a water price increase in Baja California state, which was rescinded last week amid a public backlash.
"The gas price increase was the final straw," Mario Lopez, 29, said Sunday as he and other protesters waved motorists in to Tijuana from San Diego.
Protests against the gasoline price hikes occurred elsewhere in Mexico but have died down.
HOW HAS THE MEXICAN GOVERNMENT RESPONDED?
The protests have created enormous lines to enter Mexico and raised potential security risks. Kenn Morris, president of the Crossborder Group Inc. consulting business, said Sunday's actions created a line of about 1,200 cars in San Diego but cargo traffic hasn't been affected.
Mexican authorities have taken a hands-off approach. On Sunday, there were only a few dozen demonstrators at each border crossing in Tijuana.
Shirk said the Mexican military could easily stop the protests but might further galvanize public opinion against Pena Nieto's government. He said the cautious approach recognizes Mexicans' "enormous frustration."
Only a small percentage of motorists entering Mexico from the U.S. are stopped for inspection under normal circumstances, but the takeovers have been given them an open invitation to bring what they want.
Guns and proceeds from drug sales in the U.S. are often introduced to Mexico by car. Some motorists have brought refrigerators, televisions and other goods to avoid customs duties.
This story has been automatically published from the Associated Press wire which uses US spellings