Currency impacts sent retail giant Wal-Mart's international sales down 7% in April, despite continued strong performance from Asda clothing brand George in the UK.

Wal-Mart said total company sales for April were up 2.4% to US$29.9bn, while sales for the 13 weeks to 1 May edged up 0.9% to $96.1bn.

But international sales dipped 7% to $7.1bn in April, thanks to a 20% impact from currency variations. On a constant currency basis, international sales were up 13%.

In the US, April sales were up 7.7% to $19.3bn, and comparable store sales rose 5%, with the increase partly accounted for by a later Easter.

The 13-week 3.6% increase in comps beat the company's own expectations.

The company said its Asda business in the UK had enjoyed another strong month, with good comparable store sales thanks to the growth of George apparel sales ahead of the market. Women's wear was the strongest performer, Wal-Mart said.

Elsewhere, Japan showed a comparable store sales increase in the low single digits, despite a continued fall in apparel sales thanks to the restriction of discretionary spending by consumers.

Wal-Mart vice chairman Eduardo Castro-Wright said the company's US comparable store sales illustrated "the underlying strength of the business", adding: "We are facing challenging comparisons to last year's second quarter, which benefited from the economic stimulus checks and a higher rate of food inflation.

"We expect this will be offset somewhat by higher customer traffic and improved assortments."

Wal-Mart expects to report sales of about $93bn in its first quarter results, which will be revealed on 14 May.