NEW YORK – Walmart Stores will start next week building its first Express stores, a format less than one-tenth the size of an average supercenter, according to building permits obtained by Bloomberg News.

The world’s largest retailer will begin construction March 16 on a 14,400-square-foot store in Gentry, Ark., a town of 3,158 about 20 miles southwest of the company’s Bentonville headquarters, according to the permits.

While Walmart has kept details of the new stores a closely guarded secret, Steve Restivo, a company spokesman, confirmed the location of the store openings and the timing in an e-mail. Work on similar stores in nearby Prairie Grove and Gravette will also start over the next two weeks, said town officials. The new stores will feature a pharmacy and a groceries section.

“Walmart’s U.S. store fleet is designed for yesterday’s retail wars,” Craig Johnson, president of Customer Growth Partners in New Canaan, Conn., said in an interview. “If they want to capture their rightful share of today’s shopping trips, they have to have a smaller format. God bless supercenters, but they are not designed to get in and out of within five minutes.”

Chief Executive Officer Mike Duke is seeking new avenues for growth in the United States as comparable-store sales in Walmart’s namesake stores have fallen for seven straight quarters. The retailer plans to open as many as 40 smaller units this year, and executives said last month that the first Express store would open as early as May.

The Express stores, concrete square boxes with metal roofs, will cost $1.2 million to build and sit on lots just under 5 acres, according to building permits filed in Gentry and Prairie Grove, which has a population of 4,380.

Sections for fresh produce, refrigerated foods and frozen items will go down one side and along the back of the Express store, Jackie Baker, Prairie Grove’s building and planning director, said in an interview.