South Korea's Hyundai Heavy Industries Co., the world's leading shipbuilder, said Thursday that it has posted record-high quarterly earnings in the first three months of this year on the backs of increased demand in its shipyard and engine sectors. Hyundai Heavy reported an operating income of 881 billion won ( 795 million U.S. dollars) in the January-March period, up 30.5 percent from the previous record of 675 billion won (609 million U. S. dollars) set in the fourth quarter of 2008. Net income also rose by 6.8 percent to 926 billion won (835 million U.S. dollars) in the cited period, shattering the 867 billion won (782 million U.S. dollars) record set 15 months ago, the company said.The South Korean company attributed the rise in operating and net income to the increase in high-cost shipbuilding orders and demand for plant constructions. However, sales dropped 0.5 percent from the previous quarter, standing at 5.4 trillion won (4.9 billion U.S. dollars), it added. Hyundai Heavy shares closed up 0.78 percent to 258,000 won (232.8 U.S. dollars) on the Seoul Bourse Thursday. 