More than a dozen puppies were seized from a motorist who tried to smuggle them into the United States from Mexico in his minivan, authorities said.

Many of the 28 puppies were infested with parasites, dehydrated and too weak to stand, said Dawn Danielson, director of the San Diego County Department of Animal Services.

"It's going to be touch-and-go for a lot of these puppies," Danielson said.

They were seized after a Customs and Border Protection officer noticed a paw reach out from under the front seat Tuesday evening at San Diego's Otay Mesa border crossing, authorities said.

The driver, who was only identified as a U.S. citizen, was charged with 28 misdemeanor counts of animal cruelty and cited for failure to declare a shipment, Danielson said.

The puppies, ages 3 to 6 weeks, included Chihuahuas, boxers, cocker spaniels and poodle mixes. After two weeks of monitoring, they will be placed in shelters for adoption.

It is legal to cross the border with dogs if they are declared at Customs and they have rabies shots and health records, but many are smuggled.

Puppies are often purchased in Mexico for between $50 and $150, then sold at street corners, parking lots and flea markets in Southern California for between $300 and $1,000 each, according to the Border Puppy Task Force.

The force formed in 2004 after a rash of complaints from owners who reported their dogs were turning sick and often dying.