Washington's National Zoo may be left without any giant pandas amid fears Donald Trump's ongoing trade war with China could see the bears become a political tool.

The Smithsonian National Zoo’s panda bears are one of the main draws for its two million annual visitors but the current lease of its two adults, male Tian Tian and female Mei Xiang, is due to expire next year.

The zoo's only other panda, Bei Bei, turned four this month - the age where pandas fully mature and are able to breed - and will be sent back to China for a breeding programme within the next few months under a prior agreement.

China's giant pandas have often been used to sweeten relations with international partners; Washington's National Zoo received its first pair in 1972 to commemorate President Richard Nixon's successful visit to China.

Those bears were a gift, but the current pair were sent over under a lease agreement which has since been extended multiple times but is now set to expire on December 7 2020.