Beginning Friday, travelers on Northwest Airlines will have to pay as much as $10 extra to buy tickets by phone or in person, rather than through Northwest's Web site.

Hoping to trim about $70 million in annual ticket distribution costs, the nation's fourth-largest carrier said yesterday that it would charge $5 to process tickets purchased over the phone and $10 for tickets purchased at an airport ticket counter. The fees will appear as an itemized charge on receipts, similar to a fuel surcharge.

The fees will apply only to new ticket issuance. No fee will be charged to discuss a new or existing reservation with an airport customer service agent or a telephone reservations sales agent.

The idea of charging customers to interact with an actual person is not new. As early as 1995, several banks began testing the concept to get more people to use ATM machines, but later backed off. And a number of computer manufacturers charge customers to get technical support assistance over the phone after an initial warranty period.

Airlines have been trying for several years to drive passengers to purchase tickets from their Web sites because it is less expensive than other means and requires fewer employees. Several airlines have offered extra frequent-flier miles or $5 to $10 discounts to travelers if they purchase their tickets from the carrier's Web site.

But industry watchers say this is the first time an airline is charging travelers a fee not for a convenience or a special service, but just for purchasing a ticket.

"I'm not sure why Northwest thinks they should charge people $5 for picking up the phone and calling their people," said Tom Parsons, editor and publisher of Best Fares magazine.

Also yesterday, Northwest announced that beginning Sept. 1 the airline will charge $3.75 for one-way tickets and $7.50 for round-trip tickets to U.S. and Canadian travel agents and Web sites that use global computer reservations systems. These systems allow travel agents and some travel Web sites, such as Expedia.com and Travelocity.com, to search and navigate through thousands of fares and schedules for booking flights.

And separately, United Airlines announced that beginning Oct. 15 members of its frequent-flier program who want to exchange miles for free tickets will have to pay $15 to book them through one of their reservation agents. There will be no fee if travelers book their tickets through United's Web site, United spokeswoman Jenna Obluck said.

In a statement yesterday, John Stow, president of Sabre Travel Network, the nation's largest computer reservations system, called Northwest's move "anti-consumer and anti-travel agent." Sabre, which along with Travelocity is owned by Sabre Holdings Corp. and is widely used by travel agents, said that in response it would give more prominent display on computer screens to other airlines that do not have such fees.

J. Timothy Griffin, Northwest's executive vice president of marketing and distribution, said the airline began charging the fees to be more in line with low-cost carriers, particularly JetBlue Airways and Dulles-based Independence Air.

"Since we compete with low-cost carriers on price, it is essential that we take steps to be competitive with them on distribution costs, where they currently have a clear cost-of-business advantage over Northwest," Griffin said.

But neither JetBlue nor Independence directly charges fees to book travel through their call center. Instead, both carriers, like many other airlines such as US Airways, discount the listed price of their tickets by as much as $10 if the ticket is purchased via the airlines' Web sites.

Northwest's Griffin said only 16 percent of its tickets are sold via its Web site, while JetBlue and Southwest Airlines sell about 75 percent and 55 percent of their tickets, respectively, through their respective sites. About 22 percent of Northwest's tickets are sold via its telephone reservation agents and only 2 percent of its tickets are sold at airport ticket counters. Northwest closed its city ticket offices earlier this year.

Last year, Northwest began charging its customers a $50 fee if they call one of its agents to change the date, route or time of a frequent flier ticket rather than going to its Web site, if the call is made within 30 days before departure.

Northwest's moves come as it is trying to cut its annual labor costs by $950 million. Griffin said the airline is in talks with its pilots union and hopes to have the concessions in place by the fall.

Staff researcher Richard Drezen contributed to this report.