NEW YORK — In highly orchestrated raids around the world this week, Interpol officers in Europe, drug agents in the United States and task forces from Sweden to Singapore hunted down counterfeit prescription drugs to stem a rapidly growing criminal business preying on financially pressed consumers looking for bargains.

The operation, code-named Pangea, is an effort to fight back against fraudulent businesses, which have become a $28 million industry in the United States alone.

The national crackdown uncovered nearly 800 alleged packages of fake or suspicious prescription drugs including Viagra, Vicodin, and Claritin, and shut down 68 alleged rogue online pharmacies. Some counterfeit drugs may have as much as three times more of an active ingredient than is typically prescribed; others may be placebos. Drywall material, antifreeze and yellow highway paint have been found in counterfeit pills.

The front line of the operation is deep in the bowels of a sprawling mail center in the industrial outskirts of John F. Kennedy International Airport. This week, federal agent Stephen Buzzeo, wielding a letter opener, ripped open a manila envelope lined with cardboard from a diaper package and pulled out three packages of what looked like diet pills, anxiety medicine and OxyContin, an often abused painkiller.

Hundreds of packages of potentially fake medicines were dumped into orange bins, piled on skids and stacked high around him and the half-dozen others from the alphabet soup of government agencies — ICE, CBP, FDA, DEA—hoping to intercept them before they were shipped to often unwitting consumers. Overseas, Interpol officers and task forces stormed suspected counterfeit drug warehouses and distribution centers.

“We don’t know what’s in here, actually,” Buzzeo said as he inspected the pills. “All this is shady.”

Counterfeit drugs are the latest— and potentially most dangerous — front in the long-running battle against intellectual-property crimes. Law enforcement officials said consumers typically think of counterfeited products as fake Louis Vuitton purses or Nike sneakers. Although shoes are the most common phony product, accounting for 38 percent, or $102 million, of counterfeit products seized by customs officials last year, pharmaceuticals are one of the fastest-growing categories.

In 2007, they made up about 6 percent of total seizures. Last year, they accounted for 10 percent to become the third-largest category, with an estimated market value of $28 million. Federal officials say that trend is particularly disturbing because of the health dangers that such drugs present.

“The public safety part of intellectual property has really taken off in the last couple years and become the moving force,” said John Morton, an assistant secretary of U. S. Immigration and Customs Enforcement, which spearheaded the Pangea operation. “This is a huge problem.”

Though counterfeit drugs have a history as old as snake oil, the high cost of many prescription drugs has driven some consumers to hunt for cheaper alternatives on the Internet. According to the National Association of Chain Drug Stores, a trade group, Americans spent $254 billion on prescription drugs last year, up 1.8 percent from 2007. The long-running recession has made such costs more difficult for many consumers, experts said.

Meanwhile, the rise of Internet pharmacies has expanded the marketplace and supply chain for the drugs. One site under federal investigation that is selling a “power pack” of erectile dysfunction drugs Cialis and Viagra purports to have a warehouse in New Delhi, headquarters in Canada and a license to sell medicine in the United States through Minnesota.

However, the investigation found that the site was registered in China and its server was hosted in Russia. Its headquarters had previously been listed in Louisiana. ICE agents have placed several orders and are trying to build a case against the site.

The National Association of Boards of Pharmacy maintains a list of roughly 4,000 online pharmacies it says is questionable. It also certifies legitimate sellers through its Verified Internet Pharmacy Practice sites program. Seventeen have passed the test.

“The Internet is just the wild, wild West,” said Dr. Bryan Liang, vice president of the Partnership for Safe Medicines, an advocacy group.