US retail giant Wal-Mart has posted a rise in quarterly earnings, as an improved performance by its Sam's Club warehouse unit and rapid international expansion helped to offset weaker sales at its US discount unit.

Bentonville, Arkansas-based Wal-Mart reported net income of US$2.44bn, or 56 cents per share, for the second quarter to 31 July, compared to $2.02bn, or 45 cents per share, a year earlier.

Excluding income from its recently sold McLane grocery distribution unit, Wal-Mart’s earnings were 52 cents per share, which was in line with analysts’ average estimate, reported Reuters.

Sam’s Club posted a 12.8% rise in operating profit for the quarter, despite lowering prices on hundreds of items as part of a price war with Costco Wholesale. Costco recently warned that its quarterly profits would be lower than expected, partly because of fierce pricing competition from Sam’s Club. Sam’s Club sales rose 7.7% to $8.55bn.

Wal-Mart’s total quarterly sales rose 11.3% to $62.6bn, while same-store sales rose 3.2%.

The retailer’s international division recorded the strongest growth in sales with a rise of 18.8%.