In a major blow to the tobacco industry, the US Food and Drug Administration (FDA) has moved to ban the sale of mint-flavoured cigarettes.

Public health and civil rights groups have lobbied vigorously for the ban, citing the disproportionate harms of menthol cigarettes on black Americans.

But critics fear prohibition could give rise to clandestine sales, and more confrontations with law enforcement.

The proposed ban would affect more than a third of US cigarette purchases.

A final decision though will take months - and possibly years - to implement.

The FDA's announcement on Thursday marked the agency's deadline to respond to a federal lawsuit from public health groups seeking the ban.