South Korea's flag carrier Korean Air said Tuesday it would buy a total of seven passenger planes from Airbus and Boeing for nearly $1.58 billion.

The airline said the planes -- five Airbus A330-200s and two Boeing B777-300ERs -- would cost 1.685 trillion won ($1.577 billion) and be bought between May 2011 and September 2015.

Airbus, the airliner manufacturing subsidiary of European aerospace group EADS, said Korean Air has placed a firm order for five long-haul A330-200s worth about $1 billion.

Korean Air is buying the planes as part of an aggressive strategy to win customers from regioanl rivals.

Boeing announced in March that it had also secured an order for two of its new 747-8 cargo planes from Korean Air in a deal valued at $639 million at list prices.

The airline's first-quarter net profit rose 49.5 percent from a year ago to 282.1 billion won thanks to a stronger won and gains from equity investments.

Sales rose 7.2 percent on-year to 2.82 trillion won in the period, while operating profit fell 41.2 percent to 162.9 billion won due to increased fuel costs.

Analysts forecast travel demand to Japan will remain weak in the second quarter following the March tsunami, but that it will be offset by seasonal demand on routes to China, Southeast Asia and the United States.