Fast food giant McDonald's said Tuesday it would almost double the number of restaurants in China over the next five years as it refocuses on international markets amid slowing US sales.

The Illinois-based burger chain will add 2,000 stores to its current 2,500 in China and aim for double-digit sales growth in each of the next five years, McDonald's said in a statement.

In particular, it will launch a foray into third- and fourth-tier cities, where it expects 45 percent of its China restaurants to be located by that time. 

More than 75 percent of its stores will offer delivery.

It made the announcement while also saying it had finalised a strategic partnership with Chinese conglomerate CITIC Ltd and US-based investment firm Carlyle Group.

McDonald's announced earlier this year that it would form a company with CITIC Limited, CITIC Capital Holdings and Carlyle Group to act as a franchisee for the chain’s business in mainland China and Hong Kong for 20 years.

CITIC is a vast Chinese state-owned conglomerate with interests ranging from energy and manufacturing to real estate. 

The new partnership becomes the largest McDonald's franchisee outside the US.

"China will soon become our largest market outside of the United States," McDonald's president and CEO Steve Easterbrook said in the statement.

McDonald's has been overhauling its global structure under Easterbrook to compensate for slower growth in markets such as France and the United States.

McDonald's sales took a hit in recent years as tensions over the South China Sea dented US companies' earnings in China. 

Its China business also suffered a blow in 2014 after a food safety scandal involving one of its meat suppliers.

In the China market, McDonald's also faces competition from fast-food market leader KFC.