Afghans who helped allied forces against the Taliban have been left in limbo, after the United States halted some immigration processing over the weekend.

According to a State Department cable seen by Reuters, US President Donald Trump's administration has ordered its diplomats worldwide to stop processing visas for Afghan nationals.

It comes after the shooting in Washington last week of two National Guard members, which left one dead. Authorities say the alleged shooter was an Afghan national.

• Guest: Shawn VanDiver, founder and president of AfghanEvac, an organisation that works to evacuate and resettle Afghans in the United States