'Legal pot shops'

Facebook shuts down 'legal pot shops'

It highlights the problems faced by social networks trying to set boundaries for what users can post.

The National Cannabis Industry Association said it was seeking "clearer guidelines" from Facebook.

Affected businesses should appeal to have their accounts restored, the NCIA told the Associated Press news agency.

The problem had affected all of the nine US states that had legalised recreational and medical cannabis, deputy director Taylor West added.