A Portland man arrested after allegedly stabbing another male in what he says was self-defence in Nantucket, Massachusetts on Tuesday, has been released on US$2,500 bail, according to US media reports.

The Jamaican, 39-year-old Kemar Downer, appeared in the Nantucket District Court on Wednesday morning on two charges of assault and battery with a dangerous weapon, causing serious bodily injury.

a screengrab from surveillance video showing the stab victim approaching and hitting Downer from behind before fleeing after being stabbed (Nantucket Current)