NEW YORK ( TheStreet) -- McDonald's ( MCD) shares were rising in premarket trading after the fast-food chain said that comparable-store sales rose 1.9% in August vs. 3.7% in the year-earlier period. In the U.S., comparable-store sales inched 0.2% higher last month vs. 3% last year, lifted by its popular Monopoly promotion, but still dampened by "the persistently challenging environment," McDonald's said. Comparable sales represent restaurants, whether company-owned or franchised, that have been open at least 13 months. Shares of the Oak Brook, Ill.-based company were rising 1.1% to $97.48 before the markets opened. McDonald's European operations saw a 3.3% lift in comparable sales vs. 3.1% in August 2012, fueled by the introduction of blended-ice beverages in the U.K., strong premium food events in the U.K. and Russia, and emphasis on core products in France offset by sales declines in Germany. The Asia/Pacific, Middle East and Africa segment saw a 0.5% decline last month vs. a 5.7% gain a year earlier. The segment's performance included declining sales results in Japan, China and Australia partially as well as the shift in timing of Ramadan, McDonald's said. Year to date, the company's comparable store sales are up just 0.4% across all of its regions vs. 4.4% in 2012. Total sales systemwide in August rose 2.8%, or 4.7% in constant currencies, the company said. "Ensuring that each of our strategies resonates with our customers is the key to our performance -- today and for the long-term," said McDonald's President and CEO Don Thompson. "We remain confident in the fundamental strength of the McDonald's system and our ability to connect with customers and deliver the menu choices, value and convenience they expect from McDonald's." The company said it plans to improve its U.S. results by "strengthening its value leadership," and feature new product offerings. McDonald's on Monday kicked off new "Mighty Wings" menu item. It plans to have the bone-in wings offered at its more than 14,000 nationwide locations by Sept. 24. The wings are sold in 3, 5 and 10 pieces, with prices starting at $2.99. -- Written by Laurie Kulikowski in New York. Follow @LKulikowski To contact Laurie Kulikowski, send an email to: Laurie.Kulikowski@thestreet.com. >To submit a news tip, email: email@example.com. Follow TheStreet on Twitter and become a fan on Facebook.