REDMOND, Wash. -- Microsoft Corp. said it is pulling the trigger on thousands of the 5,000 job cuts it announced earlier this year.

About 3,000 Microsoft employees were notified Tuesday that they are being laid off. And in an e-mail to employees, Microsoft Chief Executive Steve Ballmer left the door open to even more cuts.

"As we move forward, we will continue to closely monitor the impact of the economic downturn on the company and if necessary, take further actions on our cost structure including additional job eliminations," he wrote.

Company spokesman Lou Gellos said the notifications are part of the planned 5,000 layoffs that were announced in January.

About half of the 3,000 layoff notices sent out Tuesday were to employees in the U.S., Gellos said. A Microsoft official said later Tuesday that of those, 1,200 were in the Puget Sound region. the rest affect overseas employees.

The company said laid-off employees will be given severance packages, and that it expects some will be rehired as part of the 2,000 to 3,000 new jobs Microsoft is creating between now and the middle of 2010.

On April 23, the software giant said its quarterly revenue fell from the previous year for the first time in its 23-year history as a public company, while its profit dived 32 percent.

The job cuts that began earlier this mark the first time the company needed to resort to mass layoffs.

Microsoft makes most of its profit selling the Windows operating system and business software such as Office, and those divisions have been hammered over the last six months as consumers and businesses sharply cut their technology spending. The holiday quarter, which ended in December, was the PC industry's worst in six years, according to research groups IDC and Gartner Inc. In the following quarter, computer shipments sank about 7 percent.

Even the brightest spot in the PC market - tiny, recession-friendly laptops known as netbooks - had a downside for Microsoft because those inexpensive computers run a cheaper version of Windows XP, Microsoft's last-generation operating system.

Shares of Microsoft slipped 40 cents to close at $19.79.