(Adds detail on revenue, store openings)
MEXICO CITY, April 21 (Reuters) - Mexico's biggest retailer, Wal-Mart de Mexico, on Tuesday reported a 9 percent increase in its first-quarter profit as sales across its stores picked up.
The company reported a profit of 5.174 billion pesos ($339 million), compared with a profit of 4.75 billion pesos in the year-earlier period.
But as a result of higher costs, earnings came in below analysts' expectations for profit of 5.558 billion pesos, according to a Reuters poll of six analysts.
Revenue climbed 9 percent, in line with expectations, to 111.7 billion pesos, as sales at stores open at least a year (same-store sales) climbed 4.9 percent and the company opened 11 new stores in the quarter.
Walmex, which has struggled against tough competition and weak consumer spending in Mexico, last year offloaded its restaurant business and its bank in order to focus on its core supermarket business.
The company also has slowed its program of store openings since 2012, when a New York Times report alleged it had bribed Mexican officials to open stores more quickly.
Walmex shares closed up 1.96 percent at 38.98 pesos, before the results were announced.
$1 = 15.2610 pesos at end March Reporting by Elinor Comlay; Editing by Leslie Adler