“People who refuse the mask are the real heroes,” he tweeted.
Twitter said the ban was in line with its recently updated policy aimed at cutting down on harmful links. Under the new rules, the company may suspend accounts dedicated to sharing hateful content or that try to get around its blocks on sharing links to the material.
Duke was the leader of the white supremacist KKK from 1974 to 1978.
The Associated Press contributed to this report.