(Reuters) - McDonald's Corp's (>> McDonald's Corporation) sales fell at established restaurants in all regions last month, hurt by stiff competition in the United States and the fallout from a supplier scandal in Japan and China.

Worldwide sales at restaurants open at least 13 months fell 0.5 percent. Analysts on average estimated a 2.2 percent decline, according to research firm Consensus Metrix.

McDonald's shares were up nearly 1 percent in premarket trading.

Same-restaurant sales in the Asia/Pacific, Middle East and Africa region fell 4.2 percent, the company said on Monday. Analysts estimated a 6.1 percent drop.

Diners shunned the chain in China and Japan after a television news expose showed workers mishandling meat at a key supplier in China, and McDonald's scrambled to find new sources for ingredients to make its Chicken McNuggets and Big Macs.

Comparable sales in the United States declined 1 percent, less than the 1.9 percent fall analysts expected.

The world's biggest restaurant chain by revenue has been struggling to compete with resurgent rivals such as Wendy's Co (>> Wendys Co) and Burger King Worldwide Inc (>> Burger King Worldwide Inc) as well as privately held chains such as In-N-Out Burger and Chick-fil-A.

Europe's comparable sales decreased 0.7 per cent due to store closures in Russia and a weakening euro and ruble.

(Reporting by Lisa Baertlein in Los Angeles and Devika Krishna Kumar in Bangalore; Editing by Maju Samuel and Joyjeet Das)

Stocks treated in this article : McDonald's Corporation, Wendys Co, Burger King Worldwide Inc