China will buy 70 Boeing 737 airliners, a U.S. official said Saturday.

The official, Mike Green, senior director for Asian affairs on the National Security Council, would not discuss the financial details. Neither Boeing Co. nor the Chinese government made any formal announcement of the sale.

"It's a very important thing and I think it's a testament to how our approach to China is yielding real results," Green told reporters traveling in China with President Bush. "In this case, an order for 70 737 aircraft from Boeing."

Beijing often announces large purchases of American airliners in connection with visits by U.S. leaders in an effort to mollify Washington's frustration over China's surging trade surplus with the United States.