Fast Retailing Co. said Thursday it posted record net sales of ¥1.143 trillion in the business year through August thanks to robust growth of its Uniqlo casual clothing business in Asia.

It is the first time a Japanese clothing business has broken the ¥1 trillion sales mark in a single business year. Group operating profit rose 5.1 percent to ¥132.9 billion and consolidated net profit swelled 26.1 percent to ¥90.3 billion, Fast Retailing reported.

Domestic sales jumped 10.2 percent to ¥683.3 billion on increasing demand for products including Uniqlo's popular Heat Tech thermal inner wear. Operating profit, however, declined 5.4 percent to ¥96.8 billion, due partly to price discount campaigns, the operator said.

"Our sales topped ¥1 trillion for the first time, and it was driven by expanding Uniqlo operations abroad," Tadashi Yanai, president and chairman of Fast Retailing, said in Tokyo on Thursday.

Overseas sales of Uniqlo products sky-rocketed 64 percent from the previous year to ¥251.1 billion as the Yamaguchi-based company continued to expand in foreign markets. The number of Uniqlo outlets abroad stood at 446 as of the end of August, an increase of 154 stores in the past year.

Seven of Uniqlo's 10 best-performing outlets in terms of sales are now overseas, Yanai noted.

The firm's growing presence was notably seen in China, where 83 new outlets were opened, followed by South Korea with 27 and Taiwan with 20. It also opened its first Uniqlo store in Indonesia in June, in Jakarta, as well as the largest flagship Uniqlo store in the world, in Shanghai last month, that also offers low-cost brand GU and other lines.

Fast Retailing reported its other brands, including GU and Theory, logged total annual sales of ¥206.2 billion.