U.S. Defense Secretary Mark Esper is set to meet senior Mongolian leaders on Thursday in a rare visit to the strategically important nation to deepen ties, as the Pentagon seeks to implement its strategy of focusing on countering China and Russia.

On a map, Mongolia, locked between Russia and China, best represents the Pentagon's priorities over the coming decades.

Esper's visit to Mongolia, on his first international trip since being confirmed as defense secretary, highlights the importance the country is seen as playing in the region.