DETROIT (AP) -

Graco Children's Products has added 403,222 child seats to last month's recall of 3.8 million to replace faulty harness buckles.

But the added seats won't end a dispute with the U.S. government's road safety watchdog. The National Highway Traffic Safety Administration still wants Graco to add 1.8 million infant seats to the recall because they have the same buckles.

Buckles can get gummed up by food and drinks, making it difficult to remove children. In some cases parents have had to cut harnesses to get their children out. The agency says the problem increases the injury risk in emergencies.

Graco says in a letter to the agency that it found additional toddler and harnessed booster seats that should be recalled. The company still believes the infant seats should be excluded.

Graco said food and dried liquids could lead to the harness problem. An improved replacement harness is available at no cost. The company tells consumers to call its customer service team for details at (800) 345-4109 or email them at consumerservices@gracobaby.com.