March 3 (Bloomberg) -- Microsoft Corp., facing criticism for hiring foreigners while making job cuts, said it plans to keep its use of H1-B guest-worker visas at about the same level.

The company posted a letter on a blog today from general counsel Brad Smith in response to concerns voiced by Chuck Grassley, a Republican senator from Iowa. While saying it would continue using the H1-B program, Microsoft declined to answer questions about the number of foreign workers it employs and whether they were affected by reductions.

After Microsoft cut 1,400 positions on Jan. 22, Grassley wrote Chief Executive Officer Steve Ballmer demanding he fire H1- B visa holders first. Microsoft, the world’s largest software maker, has been one of the leading advocates for an expansion of the H1-B program, sending co-founder Bill Gates to lobby Congress last year.

Grassley said in a statement that while he appreciated today’s response, it lacked details.

“I’m still left without much information about how Microsoft is ensuring American workers are being protected or specifics of its H-1B hiring practices,” he said. “I’m interested in learning more details.”

Smith declined to provide a specific forecast for future levels of visa-worker employment. The Redmond, Washington-based company said less than 15 percent of its U.S. staff hold the visas.

No Change

“We do not expect to see a significant change in the proportion of H1-B employees in our workforce following the job reductions,” Smith said in the blog posting.

Technology and engineering positions currently account for about 90 percent of Microsoft’s H1-B visa holders. The employees make key contributions to its success, the company said.

Executives from Microsoft and Intel Corp., another proponent of the visa program, said last month they may have to scale back or quiet down lobbying for more visas amid job cuts and increasing U.S. unemployment.

Microsoft rose 9 cents to $15.88 at 4 p.m. New York time in Nasdaq Stock Market trading. The shares have fallen 18 percent this year.

To contact the reporter on this story: Dina Bass in Seattle at dbass2@bloomberg.net

Last Updated: March 3, 2009 17:38 EST