NEW YORK (AP) — McDonald's Corp. says strength in the U.S. and Europe drove up a key revenue figure in May, but noted that ongoing economic volatility around the world is pressuring its second-quarter results.

The fast-food chain, based in Oak Brook, Ill., also warned that foreign currency translations are now expected to hurt second-quarter earnings by 7 cents per share to 9 cents per share.

Shares of McDonald's fell $2.40 to $88.38 in premarket trading.

For May, the world's biggest hamburger chain says global sales at stores open at least 13 months rose 3.3 percent for the month. The figure is a key metric because it excludes the impact of newly opened or closed stores.

The figure was dragged down by results in the Asia-Pacific, Middle East and Africa region, where McDonald's said sales fell 1.7 percent from a year ago. McDonald's noted that it's trying to improve results in the region with locally relevant menu options and "convenience enhancements," such as delivery in some Asian markets.

The drop was offset by a 4.4 percent jump in the U.S., where demand for the new blueberry banana walnut oatmeal and Cherry Berry Chiller boosted sales.

In Europe, the figure rose 2.9 percent driven by gains in the United Kingdom, Russia and France, with the company's ongoing restaurant renovations helping improve sales.