BERKELEY, Ca (Reuters) - Amazon.com Inc is rolling out pickup points in the United States where shoppers can retrieve items immediately after ordering them, shortening delivery times from hours to minutes, the company said on Tuesday.

The world's largest online retailer has launched 'Instant Pickup' points around five college campuses, such as the University of California at Berkeley, it said. Amazon has plans to open more sites by the end of the year including one in Chicago's Lincoln Park neighborhood.

Shoppers on Amazon's mobile app can select from several hundred fast-selling items at each site, from snacks and drinks to phone chargers. Amazon employees in a back room then load orders into lockers within two minutes, and customers receive bar codes to access them.

The news underscores Amazon's broader push into brick-and-mortar retail. The e-commerce company, which said in June it would buy Whole Foods Market Inc for $13.7 billion, has come to realize that certain transactions like buying fresh produce are hard to shift online. Its Instant Pickup program targets another laggard: impulse buys.

"I want to buy a can of coke because I'm thirsty," said Ripley MacDonald, Amazon's director of student programs. "There's no chance I'm going to order that on Amazon.com and wait however long it's going to take for that to ship to me."