Vendor giant Motorola yesterday announced plans to reduce its workforce by 4000 positions this year, the company’s second major job-cut declaration in the last three months.

In conjunction with the announcement, Motorola reported that its mobile-devices unit shipped about 19 million commercial handsets during the fourth quarter—a reduction of more than 50% compared with the same period the previous year.

As a result, most of the job cuts will be made in the mobile-devices division. Of the 4000 cuts announced yesterday, 3000 will come from that unit. These workforce reductions are in addition to the 3000 announced on Oct. 30, 2008, of which 2000 will come from the mobile-devices side of the business, Motorola spokeswoman Kristine Mulford said.

Meanwhile, the other job cuts—a total of 2000, based on the announcements yesterday and during the fourth quarter of last year—will be made from other parts of the company, including the division that sells communications systems and equipment to government and public-safety entities. However, the company declined to specify how many jobs would be lost in that particular area.

“We’re not breaking it down any further,” Mulford said during an interview with Urgent Communications.

The job cuts—expected “to begin immediately,” according to the press release—are part of Motorola’s cost-reduction efforts to stabilize the company’s finances. In December, the company slashed employee benefits, and co-CEOs Greg Brown and Sanjay Jha both voluntarily took a 25% reduction in compensation.

While Motorola’s commercial devices business has struggled, the other units are performing well, according to the company press release.