US fastfood chain McDonald's has announced that global systemwide sales for McDonald's restaurants increased 5.9% in May, or 2.9% in constant currencies.

"Our global alignment around our customer-centred Plan to Win continues to deliver solid results with comparable sales for McDonald's restaurants worldwide up 1.8% in May - our 25th consecutive month of positive global comparable sales increases," said CEO Jim Skinner.

"Our US business once again posted strong results, with comparable sales up 4.2% for the month. Expanded menu choice and variety, like our new Fruit & Walnut Premium Salad, and more convenient service hours contributed to this performance. We'll continue to focus on combined initiatives to further enhance the customer experience," Skinner added.

In Europe, comparable sales slid 1.4% in May, amid a "challenging" business climate in the UK and Germany.

In Asia/Pacific, Middle East and Africa comparable sales were down 0.6%, as positive results in Australia were negatively offset by a weak performance in Japan.

"Looking ahead, we will continue to direct our efforts toward maintaining our momentum in the US and strengthening our performance around the world," Skinner said.