DALLAS, June 5 -- Alcatel said it would cut 5.6 percent of its US work force and close three US facilities. The company said the job cuts, totaling about 900, and the plant closures are expected to occur throughout the second and third quarters of 2001 and be completed by the fourth quarter. Alcatel employs about 15,900 workers in the US. The US accounted for about 23 percent of Alcatel's sales last year. "With business conditions in the US remaining tough, the need to continue to cut our operating costs remains important," said Mike Quigley, president of Alcatel Americas. "These efforts will better position us to operate more efficiently today while preparing us for more rapid growth once business conditions improve." Alcatel, which runs its Americas operations out of Dallas, employs about 130,000 people worldwide.