Boots has recorded a drop in its first-quarter UK retail sales as Walgreen’s Boots Alliance’s US arm shored up sales.

The pharmacy giant posted an 8.6% drop in its operating income in the quarter to November 30, which it attributed to a $1.3bn (£960m) loss in equity earnings to American wholesale company AmerisourceBergen.

Operating income increased 4.8% to £1.8bn (£1.3bn) on an underlying basis and sales were up 7.9% to $30.7bn (£22.7bn) during the period.

Boots recorded a 1.4% drop in its UK like-for-like retail sales in what it dubbed a “challenging marketplace”, while Boots’ UK pharmacy like-for-like sales edged up 0.1%.

Across Walgreens Boots Alliance’s international division, which comprises countries including the UK, The Netherlands, Norway and Thailand, pharmacy sales fell 0.8% in constant currency to $3.1bn (£2.3bn).

Overall retail like-for-likes declined 1% on a constant currency basis across its international estate, while like-for-like pharmacy sales slipped 0.1%.

The retail giant’s US division, which includes Walgreens, posted an 8.9% rise in sales to $22.5bn (£16.6bn) during the period, up 4.7% on a like-for-like basis.

This increase was driven by its pharmacy division, which rose 14.1% and accounted for nearly three quarters of the group’s overall US sales.

US retail sales fell 2.8% year-on-year.

Executive vice-chairman Stefano Pessina said: “I am pleased that we delivered another strong performance in the first quarter, led by continued prescription volume and market share growth in Retail Pharmacy USA.

“At the same time, we continue to position our company for future growth with the acquisition of the first Rite Aid stores following regulatory clearance for the transaction in September.”