Chinese and U.S. aviation officials Saturday signed a landmark air services agreement that will more than double the number of airlines flying between the two countries. The deal will permit a nearly five-fold increase in China-U.S. air services over the next six years.

The new agreement, which was signed by Yang Yuanyuan, chief of the Civil Aviation Administration of China, and Norman Y. Mineta, U.S. transportation secretary, in Beijing, will allow five additional airlines from each country to serve the China-U.S. market over the next six years.

The United States may name one additional all-cargo airline, while China may name either a passenger or cargo airline to start service later this year.

As a result of the agreement, the U.S. Department of Transport authorized United Airlines and Northwest Airlines to operate seven flights each week between the United States and China.

Northwest will operate a new daily flight from Detroit to Guangzhou — the first U.S.-carrier passenger service to the city — with a stopover in Tokyo, while United will begin a new daily nonstop service between Chicago and Shanghai.

The agreement will allow a total of 195 new weekly flights for each country — 111 by all-cargo carriers and 84 by passenger airlines — growing to a total of 249 weekly flights at the end of a six-year phase-in period.