TOKYO (AFP) - Japanese drinks giant Suntory said on Monday that it would buy the top-selling Lucozade and Ribena brands from British drugs firm GlaxoSmithKline for US$2.1 billion (S$2.68 billion).

The deal, part of Suntory's bid to expand overseas to counter a shrinking domestic market, was expected to be completed by the end of the year, Suntory said.

Energy drink Lucozade and the Ribena juice brand would help Suntory's food and beverage unit move closer to hitting a 2 trillion yen (S$25.8 billion) annual sales target in 2020, it said.

The unit, which debuted on Tokyo's stock exchange in July after a US$3.9 billion share sale, said it would "actively pursue" more cross-border deals.

"In our international business, we are expanding our business in emerging markets and strengthening our business platform in order to improve profitability by further developing our existing brands and growing our production and sales," the company said in a statement.