Wal-Mart Stores Inc posted higher-than-expected quarterly profit on Tuesday, as strong growth in international markets helped offset a greater-than-expected drop in comparable sales at its U.S. discount stores.

The world's largest retailer said earnings were $3.32 billion, or 88 cents a share, for the fiscal first quarter ended April 30. That compares with $3.03 billion, or 77 cents a share, a year earlier and the 85 cents per share expected by analysts, according to Thomson Reuters I/B/E/S.

U.S. sales at discount stores open at least a year, a key measure of a retailer's business, fell 1.4 percent. Analysts on average had forecast a 0.6 percent drop as of Monday, according to Thomson Reuters. In February, Wal-Mart forecast those sales at down 1 percent to up 1 percent.

Wal-Mart's U.S. discount stores have lost sales to competitors in recent months as consumers have begun shopping more for discretionary items like clothing and home furnishings, rather than focusing on getting low prices for key everyday items like food and paper towels that helped boost Walmart stores during the recession.

Wal-Mart shares edged higher in premarket trading.

(Reporting by Brad Dorfman, editing by Gerald E. McCormick)