The Taliban celebrated Afghanistan's Independence Day on Thursday by declaring they beat the United States, but challenges to their rule ranging from running a country severely short on cash and bureaucrats to potentially facing an armed opposition began to emerge.

The holiday commemorates the 1919 treaty that ended British rule in the central Asian nation.

As wary Afghans marked the day, flag-waving protesters took to the streets of more cities as popular opposition to the Taliban spread, and a witness said several people were killed when the militants fired on a crowd in Asadabad in the east.

“Our flag, our identity,” a crowd of men and women waving black, red and green national flags shouted in the capital Kabul, a video clip posted on social media showed.

With many ATMs out of cash and worries about rising food prices in the nation of 38 million people reliant on imports, the Taliban face all the challenges of the civilian government they dethroned without the level of international aid it enjoyed.

In a tweet, Taliban spokesman Zabihullah Mujahid announced the "declaration of the Islamic Emirate of Afghanistan on the occasion of the 102nd anniversary of the country's independence from British rule".

Header image: An Afghan waves the national flag as they celebrate the 102th Independence Day of Afghanistan in Kabul on August 19. — AFP