A visitor looks at a display of miniature Boeing passenger aircraft at an aviation expo in Beijing. [Photo/Agencies]

SEATTLE -- A group of Chinese companies signed Tuesday a deal with US plane maker Boeing to buy 300 Boeing aircraft.

The deal was reached during Chinese President Xi Jinping's first state visit to the United States which kicked off on Tuesday morning.

Meanwhile, the Commercial Aircraft Corporation of China Ltd also signed a cooperative document with Boeing to build a 737 aircraft completion center in China.