WASHINGTON — Judging by its Web site, Fairview Lending Group looked like a reputable company, a 35-year-old loan adjuster, Michelle Ford, said. Over two months, Ms. Ford, from Charlotte, N.C., sent Fairview $2,856 in collateral for a $20,000 loan that never materialized.

A 23-year-old resident of suburban Washington, Dykelia Hall, needed money for Christmas presents and turned to American Allied Financial, which claimed to be located in a Washington office building. She put $600 down on a $6,000 loan that she never received.

A resident of San Jose, Calif., Monica Aliman, 34, wired American Allied Financial her November rent money in the belief that she would receive her $8,000 loan in time to pay her landlord. She said she thought it was odd she had to send money to get money.

“I thought I just didn’t know enough about the loan process,” Ms. Aliman said.

Ms. Ford, Ms. Hall, and Ms. Aliman are among thousands of people who have fallen prey to what consumer watchdogs say is a recent surge in advance-fee loan scams.

The scam has been around for decades. Many consumers are not aware that it is illegal to charge lending fees in advance. People with poor or no credit are enticed by ads, direct mail solicitations, or telemarketing calls promising fast money at favorable terms.

The Internet has made it easier for scam artists to find victims. Consumers are drawn in by legitimate-looking Web sites, complete with privacy policies, customer service numbers, and online loan applications. Soon after filling out applications, the victims typically receive phone calls saying their loans were approved, but because of their credit ratings, they must first wire deposits or collateral.

Once the consumers oblige, the promised loans never materialize. The victims can no longer get in touch with the company and, having given out their bank account and Social Security numbers, are also vulnerable to identity theft.

In 2005, consumer protection agencies such as the Federal Trade Commission, the Better Business Bureau and the National Association of Attorneys General received nearly 14,000 complaints about advance-fee loan and credit-protection scams, according to Consumer Sentinel, a government clearinghouse that collects data on consumer fraud and identity theft. Consumer protection agencies have issued warnings about advance-fee loan scams in Virginia, Nebraska, Ohio, Michigan, and Oklahoma during the past six months.

Law enforcement officials have trouble tracking down loan scammers, who typically operate outside the country, creating a roadblock of jurisdictional issues. The president and chief executive of the Better Business Bureau for metropolitan Washington, Edward Johnson III, said, “These rogue operatives move quickly and reopen under various names. The address provided by such firms are often false, nonexistent or drop boxes.”

The bureau said it has received more than 140 complaints this year about advance-fee loan scams, compared with 22 last year. It has also received more than 3,130 inquiries about advance-fee loan operations, up from 810.

Many of the complaints are about companies using Washington-area addresses.

Fairview Lending, for example, claimed to share the same Bethesda, Md., office tower as BET founder Robert Johnson’s RJL Cos. and the law firm Lerch, Early & Brewer. Its name doesn’t appear on the building directory. The building’s management company, Realty Management, did not return phone messages. Fairview’s phone number was not working as of Thursday.

American Allied Financial told consumers that it was located at 2100 Pennsylvania Avenue NW. Since mid-November, the concierge has turned away several angry consumers looking for American Allied’s offices. A spokeswoman for George Washington University, which owns the office building, said it has never had a tenant called American Allied.

The company’s toll-free phone number was not working on Thursday, and its Web site went dark earlier this week after the D.C. attorney general alerted the company hosting the site that American Allied was using a false address and hadn’t responded to the agency’s request for a response to consumer complaints.

Better Business Bureau letters addressed to Fairview and American Allied were also returned, Edward Johnson said.