California-based Atmel laid off 266 employees from its Colorado Springs semiconductor plant Tuesday, its second round of layoffs in five months that has eliminated more than 500 jobs amid a worse-than-expected sales decline.

The plant employed 1,480 people before the layoffs, which come as the Colorado Springs job market continues to deteriorate - the local unemployment rate jumped to a 21-year high of 8.6 percent in March, with more than 26,000 people out of work.

"Atmel, like many companies in our industry, is seeing the effects of the broader economic decline, and factory utilization is below what we anticipated in December," said a statement from the company issued Tuesday. "Although difficult, given the impact on employees, these actions are necessary to ensure Atmel's competitiveness. Atmel has many hardworking and dedicated employees, and we are committed to helping smooth the transition for those affected, including providing severance and outplacement services."

The company told the plant's employees to attend a meeting Tuesday afternoon and hired Colorado Springs police to provide security in the parking lot of its plant at 1150 E. Cheyenne Mountain Blvd. in southwest Colorado Springs. All but one of the positions eliminated were in the plant's manufacturing operations. The company also cut 27 jobs from the 520 employees at its San Jose, Calif., headquarters.

Atmel's local plant is the only semiconductor manufacturing operation left in the Colorado Springs area after Intel halted production at its local plant in 2007.

The plant makes microcontrollers used in touch screens, battery-management systems and other devices, It also makes nonvolatile memory chips that retain information when power is lost, as well as application-specific semiconductors and other chips used in the automotive industry.

Atmel laid off 245 employees at the plant in December and shut down for 11 days beginning Dec. 24 as part of a companywide restructuring program that affected 11 percent of its 6,800 employees and was designed to save $18 million a year.

The company also imposed a hiring freeze except for "critical" positions and put "strict controls" on discretionary spending amid a double-digit percentage revenue decline.

The Atmel job cuts come just days after Agilent Technologies cut 250 of its 1,450 employees in Boulder, Colorado Springs, Englewood and Loveland as part of companywide restructuring that will eliminate 2,700 jobs, or 25 percent of the work force in its electronic-measurement operations, said Jean Mooney, an Agilent spokeswoman in Loveland.

The number of cuts in the Springs, where Agilent employs 540, has not been determined, she said.

The company will continue to notify affected employees through next month, with the layoffs phased in throughout the rest of the year, Mooney said. Most local Agilent employees work in the electronic-measurement unit or in administrative and support jobs, she said.

Agilent announced the cuts in March based on a forecast that revenue from the electronic-measurement operations would decline 30 percent this year to the lowest level in the company's 10-year history.

The move will cut costs for the unit by $300 million a year.