By Maarten van Tartwijk

AMSTERDAM--Newly merged supermarket operator Royal Ahold Delhaize NV (AD.AE) reported sales growth in the fourth quarter as a strong performance in the Netherlands helped to offset mixed results in the U.S.

The company said Thursday that pro forma sales rose 2.8% to 15.5 billion euros ($16.5 billion) in the last three months of 2016 after adjusting for currency swings and an extra selling week in the same period a year earlier.

Comparable sales grew by 6.6% in the Netherlands, which Ahold Delhaize attributed to an improved performance of its Albert Heijn supermarket chain and strong online sales.

In the U.S., where the retailer generates most of its revenue, growth was subdued partly as a result of falling food prices. Comparable sales at Delhaize America rose 2.2%, while Ahold USA reported a 0.2% decline.

Ahold Delhaize reiterated its full-year expectation of an underlying profit margin to be "slightly ahead" of last year, while its free cash flow will reach around EUR1.3 billion. The company will publish its earnings report for the full year on March 1.

-Write to Maarten van Tartwijk at maarten.vantartwijk@wsj.com

(END) Dow Jones Newswires

January 19, 2017 02:00 ET (07:00 GMT)