General Motors will cut production of its slow-selling Saturn L Series by about 40% in June and lay off some workers at the Wilmington, Delaware, plant that builds the mid-size car, Reuters said.

GM will stop work at the Delaware plant for four weeks from May 12, resulting in temporary layoffs for about 2,100 of the facility's 2,270 workers, Saturn spokeswoman Sherrie Childers Arb told Reuters.

When production resumes on June 9, GM will cut the assembly line-speed at the plant by about 40% to around 33 cars per hour, down from about 57 currently. As a result, an undetermined number of workers will be laid off indefinitely, Childers Arb also told the news agency.

"The sales are slowing down," she reportedly said. "In the part of the mid-size market where the L Series competes, the market is actually slowing a bit."

Reuters said the temporary shutdown is the second this year for the Wilmington plant. GM halted production for two weeks in March.

Inventories of unsold L Series cars hit 160 days' supply, above the usual 60 to 70 days supply heading into the busy spring selling season, according to Reuters. This was despite GM's high retail incentives -- $3,000 cash back or interest-free financing for up to five years on the L Series.

Reuters said the L Series, Saturn's first entry into the highly competitive mid-size car segment [and loosely based on the previous generation GM Europe Opel Vectra], has suffered weaker-than-expected sales since it went on the market in 1999. It competes with the Honda Accord and the Toyota Camry.

L Series sales fell 17% last year to 81,172 units in the United States, far below the 200,000 capacity at the Wilmington plant, Reuters added.