WASHINGTON — Countrywide Financial and IndyMac Bancorp, two of the nation's largest mortgage lenders, announced plans to sharply reduce their workforces in coming months as they try to cut costs in a turbulent mortgage market.

Countrywide, the nation's biggest mortgage lender, said yesterday it expects to cut 10,000 to 12,000 workers — or about 20 percent of its workforce — in the next three months.

IndyMac said it will offer voluntary severance packages to be followed by layoffs as it tries to shed 1,000 workers, or about 10 percent of its staff.

The announcements came on the day the Labor Department said the nation lost 4,000 jobs in August, led by the slump in housing.