With American corporations under increasing pressure to cut costs and build global supply networks, senior IBM officials told their corporate colleagues around the world in a recorded conference call that IBM needed to accelerate its efforts to move white-collar, often high-paying, jobs overseas, even though that might create a backlash among politicians and its own employees.

During the call, IBM's top employee-relations executives said 3 million service jobs were expected to shift to foreign workers by 2015 and that IBM should move some of its jobs now done in the United States, including software design jobs, to India and other countries.

"Our competitors are doing it, and we have to do it," Tom Lynch, IBM's director for global employee relations, said in the call.

A recording was provided to the New York Times recently by the Washington Alliance of Technology Workers, a Seattle-based group seeking to unionize high-tech workers. The group said it received the recording, which was made by IBM, from an IBM employee upset about the plans.

IBM's internal discussion about moving jobs overseas provides a revealing look at how companies are grappling with a growing trend that many economists call offshoring. In decades past, millions of American manufacturing jobs moved overseas, but in recent years the movement has also shifted to the service sector, with everything from low-end call center jobs to high-paying computer chip design jobs migrating to India, China, Russia, the Philippines and other countries.

Officials at IBM and many other companies argue that creating more jobs in lower-cost locations overseas keeps their industries competitive, holds costs down for American consumers and helps to develop poorer nations while supporting overall employment in the United States by improving productivity and the nation's global reach.

"It's not about one shore or another shore," said Kendra R. Collins, an IBM spokeswoman. "It's about investing around the world, including the United States, to build capability and deliver value as defined by our customers."

But in recent weeks, many politicians in Washington, including some in the Bush administration, have begun voicing concerns about the issue during a period when the economy is still weak.

In the IBM conference call, which took place in March, the company's executives were particularly worried that the trend could spur unionization efforts.

The IBM officials also warned that when workers from China come to the United States to learn to do technology jobs now being done here, some American employees might grow enraged about being forced to train the foreign workers who might ultimately take away their jobs.