OAK BROOK, Ill. -- McDonald's says a key sales metric was flat in April in the U.S., as the world's largest hamburger chain worked to fend off competitors and improve service in its restaurants.

Global sales at locations open at least 13 months rose 1.2 per cent, boosted by stronger performance overseas.

Back at home, McDonald's Corp. has been dealing with intensifying competition from long-time rivals like Burger King and Wendy's, which have revamped their menus and stepped up marketing. It's also facing a shift in eating habits, with places such as Chipotle positioning itself as a higher quality alternative to traditional fast-food.

Over the past year, McDonald's executives have also conceded that the chain introduced too many items too quickly, which resulted in slower service and inaccurate orders. But CEO Don Thompson has said the company is working with franchisees to address those problems, in part by ensuring restaurants have appropriate staffing.

Looking ahead, the company plans to underscore popular items like the Big Mac in advertising. It's also emphasizing its breakfast menu as rivals such as Taco Bell look to take a bigger share of the growing breakfast market.

For April, sales rose 2.9 per cent in the unit encompassing the Middle East, Africa and the Asia Pacific, helped by results in China.

Europe sales rose 0.3 per cent, lifted by results in the United Kingdom and growth in France.

McDonald's, based in Oak Brook, Illinois, has more than 35,000 locations around the world.

Its shares slipped 27 cents to $101.69 in afternoon trading Thursday. Its shares had been up almost 6 per cent so far this year though Wednesday's close.