SEOUL, July 13 (Yonhap) -- The number of smartphone subscribers in South Korea hit 15 million this week, according to data from the country's three mobile operators released Wednesday.

South Korean smartphone subscribers numbered 15.35 million as of Monday, including 7.8 million users at the industry leader SK Telecom Co., 5.45 million at KT Corp. and 2.1 million at LG Uplus Corp., the mobile carriers said.

The country reached the milestone less than four months after the number of users passed 10 million in late March, highlighting a recent spike in smartphone adoption. It took roughly 17 months to hit the 10 million mark.

The iPhone's arrival in the country at the end of 2009 kick-started South Korea's smartphone market. Although introduced slowly, the smartphone caught on nationwide at a faster clip than in most other countries.

The data also showed that the market for the feature-packed, handheld computing devices is the fastest growing segment in the country's saturated wireless market, which is estimated at about 52 million users.

On the back of the robust demand, mobile operators are confident about meeting their smartphone subscriber targets by the end of the year.

SK Telecom aims to lure a total of 10 million smartphone users by December, while LG Uplus seeks to add another 0.9 million. KT, the No. 2 mobile carrier and the dominant fixed-line operator, revised up its year-end target by 30 percent to 8.5 million.

Based on mobile operators' forecasts, the number of smartphone users in South Korea will likely hit 20 million at the end of this year, accounting for about 40 percent of the overall wireless market.