Snap curfew imposed on troubled outback town after four off-duty cops were allegedly attacked by angry mob

Northern Territory Police have ordered another snap lockdown for Alice Springs after a string of incidents, including the alleged assault of four off-duty officers by a group of about 20 youths

The curfew on the outback town will last from 10pm till 6am for three days and apply to adults and children.

NT Police Commissioner Michael Murphy announced the curfew on Monday after Sunday morning's incident.

It's the second time this year a curfew has been imposed on Alice Springs, following a 14-day lockdown around Easter after 150 people allegedly rioted through the streets.

During their walk, the four off-duty police officers - three women and a man - were allegedly approached from behind by a group of about 20 male youths who proceeded to assault them.

One of the female off-duty officers was pulled to the ground and had her bag allegedly stolen.

Another woman was allegedly punched in the face and kicked multiple times before her mobile phone was taken.

The male off-duty officer was also punched and kicked multiple times.

The four off-duty officers returned to their accommodation where they contacted police.

Two of the women were taken to Alice Springs Hospital for treatment of minor wounds.

Police are urging anyone who may have witnessed the incident or has information to come forward.

Under laws introduced in May, the NT's police commissioner has the power to declare 72-hour lockdowns to respond to "public disorder".