SEOUL, South Korea (AP) — Kia Motors posted a 61 percent surge in quarterly profit, boosted by sales of popular new models in South Korea and increased demand overseas.

Kia, an affiliate of Hyundai Motor Co., earned 557.8 billion won ($471 million) in the April-to-June quarter, it said Friday. Net profit was 347.1 billion won the year before.

Sales in the second quarter totaled 5.77 trillion won, up 23 percent from 4.68 trillion won a year earlier.

The company's results came a day after Hyundai, South Korea's largest automaker, said second-quarter profit soared 71 percent to a record 1.39 trillion won ($1.2 billion) on a double-digit jump in global sales.

Hyundai and Kia, which together form the world's fifth-largest automotive group, have expanded aggressively overseas in recent years. Kia has plants in China and Slovakia and began production in the U.S. last year. Hyundai has factories in China, India, Turkey, the U.S. and the Czech Republic.

Kia said in a release that its popular K5 sedan helped boost sales in South Korea during the first half of the year. Overseas, the company said demand increased in China, the U.S., Europe and other regions.

The automaker sold slightly over a million vehicles in the first half, up 34 percent over the year before. Kia said it was the first time to surpass the million sales mark for a half-year period.

"Results in the first half improved thanks to increased sales volume and the effect from new models," said Kia finance chief Lee Jae-rok.

Shares in Kia Motors, which released results during morning trading, rose 2.3 percent to close at 30,900 won. The stock price tripled in value in 2009.