An Apple Inc store in Beijing. The company reported slower sales growth in China during the first quarter of this year. [Zhu Xinxing / China Daily]

Apple Inc reported slower sales growth in China during its most recently completed quarter, as the gadget maker saw its first profit decline since 2003.

For the company's second fiscal quarter, which ended on March 30, net profit was $9.55 billion, or $10.09 a share, down 18 percent from the $11.6 billion, or $12.30 a share, recorded a year earlier. Revenue increased 11 percent to $43.6 billion.

Sales of Apple's most popular devices remained strong during the recent quarter.

It sold 37.4 million iPhones, compared with 35.1 million in last year's fiscal second quarter. Sales of iPads totaled 19.5 million, up from 11.8 million a year ago.

According to DRAMeXchange, a Taiwan-based company that tracks production of microchips, South Korea's Samsung Electronics Co accounted for 30 percent of the global chip market during this year's first quarter. Apple had a 17.3 percent share, compared with 16.1 percent in the fourth quarter of 2012.

A slower pace of sales in China raised fresh concerns that Apple is feeling the effect of reduced demand in what remains its fastest-growing and second-biggest market.

However, Apple said revenue increased 11 percent to $8.8 billion in the mainland, Hong Kong and Taiwan, which was much slower than in its fiscal first quarter, when the iPhone 5 was introduced in China. In that period, sales sailed at 67 percent, far outpacing growth of 15 percent in the Americas and 11 percent in Europe.

About two-thirds of Apple's revenue came from international sales in the latest quarter.

In China, iPad sales soared 138 percent year-on-year.