Caterpillar Inc. says it will lay off 50 more workers at its East Peoria plant in addition to the 120 layoffs announced last week.

Company spokeswoman Lisa Miller says all 170 layoffs are effective June 29 and are the result of "weak market conditions." She says Caterpillar plans to offer support services to the impacted employees.

The announcement, made Monday, marks the third round of layoffs this year at the plant in East Peoria. An additional 120 workers were laid off in January.

According to reports, Caterpillar announced in May that it would lay off 150 workers at its Decatur plant due to weak demand for the mining equipment manufactured there.