Walmart Inc. will build four new e-commerce warehouses in a push to speed deliveries, using an automated system to pick out items while also creating more than 4,000 jobs.

In combination with traditional fulfillment centers, the new facilities will enable Walmart to reach 95% of the US population with next- or two-day shipping, according to a company statement Friday. That’s up from about 75% now, a company spokeswoman said.

Walmart is bolstering its delivery capabilities to keep up in online sales with Amazon.com Inc. and other rivals. The new warehouses — developed with technology partner Knapp — will also ease the strain on employees by cutting a manual 12-step process for fulfilling orders to just five. That will mean less walking and lifting.

The new facilities will combine “people, robotics, and machine learning to set an entirely new precedent for us on the speed of fulfillment,” David Guggina, senior vice president of innovation and automation at Walmart’s US unit, said in the statement.

The company declined to say how much it will invest in the project. The first warehouse will open in Joliet, Illinois, this summer. Additional centers will be built in Indiana, Pennsylvania and Texas over the next three years.

Walmart has been working to fine tune the technology at an existing warehouse in Pedricktown, New Jersey.