March auto sales at Hyundai Motor Co <005380.KS> jumped more than a third, thanks to new model launches and strong shipments from plants in China and India, it said on Thursday, sending its shares to a three-month high.

The South Korean carmaker unveiled a revamped Sonata mid-size sedan in the United States in February, which helped push U.S. sales to a record last month.

The firm is likely sold about 47,000 to 48,000 vehicles in the U.S. market last month, up as much as 18 percent from a year earlier, its U.S. CEO said on Wednesday.

The monthly results eased concerns that aggressive marketing from Toyota Motor Corp <7203.T>, which offered deep discounts in March after a series of recalls, could hit Hyundai's strong sales growth in recent months.

Hyundai sold 317,973 vehicles last month, up 36 percent from a year ago and 27 percent higher than February.

The upgraded Sonata sedan and sports utility vehicle Tucson led the shipment growth, forcing the world's No. 4 automotive group to run its U.S. plant in Alabama almost at full capacity for the first time since it was launched in 2005, analysts said.

Its affiliate Kia Motors <000270.KS>, in which Hyundai Motor has a 35 percent stake, said it sold 173,095 units in March, up 55 percent from a year earlier.

Shares at Hyundai, the third-largest stock on the domestic bourse, rose 5.6 percent to as high as 122,000 won, its strongest intra-day level since December 30, 2009, before closing up 4.8 percent.

(Reporting by Kim Yeon-hee; Editing by Jonathan Hopfner)