NEW YORK: Delta Air Lines will buy a stake in China Eastern Airlines as the two carriers strengthen their partnership serving the United States and China, the companies announced.

Under a preliminary agreement, Delta will invest $450 million to acquire a 3.55 percent stake in China Eastern and will be given an observer seat on the Shanghai-based airline’s board of directors.

The agreement depends on reaching a final marketing deal and approval by each carrier’s board.

“Delta’s relationship with China Eastern is long-standing. We share a vision that will create the most profitable, enduring franchise between the US and China, with world-class customer service,” said Richard Anderson, Delta CEO, in a statement.