NEW YORK — McDonald’s said a key sales figure climbed 3.7 percent in August, as the fast-food chain emphasized the value of its menu offerings amid the challenging global economy.

The world’s biggest hamburger chain said Tuesday that its breakfast menu and value items pushed up sales by 3 percent in the U.S. Last month, the figure had dipped 0.1 percent in the region after the company said its promotions failed to drive growth.

McDonald’s has been intensifying its “messaging around value,” noted Andy Barish, a Jefferies analyst.

In Europe, which is McDonald’s biggest market and accounts for 40 percent of its business, sales at restaurants open at least 13 months was up 3.1 percent on strength in the U.K., France and Russia. The company said its sponsorship of the London Olympics helped lift results.