NHN Corp., South Korea's top Internet portal operator, said Thursday its first-quarter net profit jumped

15.6 percent from a year earlier, buoyed by increased revenue from advertising and messenger services.

Net profit reached 157 billion won ($145 million) in the January-March period, compared with a profit of 136 billion won the previous year, NHN said in a regulatory filing.

Revenue rose 17.6 percent on-year to 673 billion won in the first quarter, and operating profit gained 10.5 percent to 191 billion won in the cited period.

NHN attributed the stronger bottom line to growing profit from its search advertising business and messenger services.

Shares of NHN were trading at 299,000 won on the Seoul bourse as of 9:05 a.m., down 0.17 percent from the previous session's close. The first-quarter earnings were released before the market opened.

Revenues from its search advertisements accounted for 49 percent of its total sales to reach 328 billion won in the first quarter, up 11 percent from a year earlier.

Sales from display ads rose 2.4 percent on-year to reach 79 billion won, with those from its online game business rising 5 percent to 156 billion won over the cited period.

The company also said other IT services, such as its flagship messenger service LINE, shored up its first-quarter earnings, with revenues from the services more than tripling to 111 billion won in the first quarter from a year earlier.

"Overseas sales, backed by the LINE messenger service, posted a strong growth in the first quarter," the company said. "We will continue to rack up better results from mobile and global businesses as well in the future."

NHN's free messenger application LINE broke the 150-million download mark last month as worldwide smartphone users rushed to connect with one another through the mobile messenger service.

The milestone came four months after the service drew 100 million users in January. The free messenger service was launched in June 2011.

NHN said revenues from its LINE messenger services reached 68.4 billion won in the first quarter, up 60 percent from the previous quarter.

A weaker yen limited the sharp rise of LINE services-related sales, it said. Around 80 percent of LINE-related services comes from Japan. (Yonhap News)