FILE PHOTO: A customer shops for a turkey at a Walmart store in Chicago, Illinois, U.S., November 20, 2018. REUTERS/Kamil Krzaczynski

(Reuters) - Walmart Inc WMT.N said on Thursday it would expand the roll out of its "unlimited" grocery delivery service to 1,400 stores across the United States, as competition intensifies among retailers to deliver online orders faster.

The retailer’s service gives customers the option to pay a yearly $98 fee, or a monthly $12.95 fee, to get grocery orders. The service will be available in more than 1,600 stores in the U.S. and over 50% of the country by the end of the year.

In June, Target Corp TGT.N expanded its same-day delivery using Shipt, the membership-based grocery delivery platform it bought in 2017, to its online members, where customers pay an annual fee of $99 or $9.99 per order.

Walmart began piloting “unlimited” grocery delivery service in four markets – Houston, Miami, Salt Lake City and Tampa earlier this year, and said it employs more than 45,000 shoppers to run the service.