Amazon has begun discouraging customers from buying books by Malcolm Gladwell, Stephen Colbert, J. D. Salinger and other popular writers, a flexing of its muscle as a battle with a publisher spills into the open.

The Internet retailer, which controls more than a third of the book trade in the United States, is marking many books published by Hachette Book Group as not available for at least two or three weeks.

A Hachette spokeswoman said on Thursday that the publisher was striving to keep Amazon supplied but that the Internet giant was delaying shipments “for reasons of their own.” Hachette is one of the largest New York houses, publishing under the Little, Brown and Grand Central imprints, among many others.

The affected books are a mixture of new and old. A just-published memoir, “Everybody’s Got Something,” by the “Good Morning America” anchor Robin Roberts, is taking as long as three weeks to ship, customers were told. So is Stephen Colbert’s “America Again: Re-becoming the Greatness We Never Weren’t.”