British fashion group Burberry on Wednesday reported a rise in second-quarter sales, boosted by its online division, but cautioned that currency fluctuations would hit profits this year. Revenues at the luxury retailer rallied 19 percent to £1.3 billion ($2.2 billion, 1.6 billion euros) in the six months to the end of March, compared with the same part of the prior financial year, Burberry said in a trading update. "We are pleased with our second half performance ... underpinned by the planned increase in investment in offline and online retail, innovative customer service and marketing," said chief executive Angela Ahrendts. She added: "While current exchange rates are a material headwind in what remains an uncertain macro environment, our continued global brand momentum provides an excellent foundation for the future." Burberry had already warned in January that it would be hampered by the strong pound, which costs the group more to convert other currencies back into sterling. The London-listed firm, famous for its trademark red, camel and black check design on luxury clothes and handbags, has undergone huge expansion into emerging markets under Ahrendts. Investors cheered the trading update with shares in the luxury retailer rising 2.67 percent on the London stock exchange to end the day at 1,460 pence. Ahrendts is due to leave Burberry in mid-2014, after eight years at the helm, to become head of retail at Apple. She will be replaced by Burberry's chief creative officer Christopher Bailey.