Following Hyundai Motor, affiliate Kia Motors reported all-time high quarterly earnings on the back of its robust vehicle sales in the overseas market.

Kia said Friday that its operating profit reached 1.12 trillion won ($1 billion) during the first quarter of 2012, up 33.4 percent over the same period last year.

The carmaker also saw its net profit climb by 26 percent to 1.2 trillion won. Its sales came to 11.7 trillion won.

On a quarterly basis, the figures for the operating profit, net profit and sales marked record-high.

“Thriving sales of models including the Morning, K5 and Sportage R helped it sell 690,830 vehicles worldwide in the first three months of this year,” a company spokesman said.

He said sales were also bolstered by the improved brand image of the carmaker in major markets including Europe and the United States.

Total sales, including exports of cars made both domestically and in overseas factories, reached 575,457, up from 493,662 units a year ago.

Kia saw their February sales in the U.S. market reach an all-time high. Kia Motors, an affiliate of Hyundai Motor, reported 37.3 percent growth with sales of 45,038 units in the world’s biggest automobile market, compared to 32,806 units a year before.

The K5 sedan, dubbed the Optima in North America, took the lead in noteworthy sales. Kia sold 11,558 units of the midsize sedan. The year-on-year sales growth of the K5 came to 138.6 percent.

Its sales at home, however, contracted 8 percent to 115,373 vehicles.

The company said the launch of its K9 premium, rear-drive, luxury sedan next month would help boost domestic sales.

On Thursday, Hyundai Motor said it posted 2.28 trillion won in operating profit during the first quarter of 2012, up 24.9 percent from the same period last year.

By Kim Yon-se (kys@heraldcorp.com)