South Korea's flag carrier Korean Air said Tuesday it will buy 25 aircraft from Boeing Co. for around US$5.5 billion.

Under the deal, Boeing will deliver 15 passenger jets and 10 freighters to Korean Air — the world's largest air cargo carrier — over a 10-year period from 2009, Korean Air said in a statement.

"The addition of Boeing's aircraft to our fleet will play an integral part in our development to become a leader in the world's aviation industry," Korean Air's chief executive, Cho Yang-ho, said in a statement.