NEW YORK -- Caterpillar Inc, the world's biggest maker of heavy machinery, said on Monday increasing demand will require the company to bring back some employees who were laid off during the economic downturn.

Caterpillar has already brought back some workers, and estimates about 550 laid-off workers will return by the end of next year, citing signs of recovery in the global economy.

However, about 2,500 workers laid off from the company will be offered separation packages. The company did not specify which facilities were affected.

"It's important to remember that we are not close to the record-breaking demand we experienced from 2004 to 2008," Chief Executive Jim Owens said in a statement.

The company, which has parted company with about 34,000 full-time and contract workers because of production cuts and falling sales, also repeated the sales and earnings targets it introduced last week.