Canberra, Nov 5 : Australia's Northern Territory (NT) has introduced Covid restrictions after reporting its first locally-acquired case. Michael Gunner, chief minister of the NT, on Thursday night announced that an unvaccinated man in his 20s was diagnosed with the virus in Katherine, about 300 km south of the capital Darwin, Xinhua news agency reported. He said the man has not travelled outside the NT recently. "We don't know where and we don't know when but this is community transmission," Gunner told reporters. "He has caught it from someone in the territory but we don't know who." It is the first confirmed case of community transmission in the NT since the start of the pandemic. Gunner said the man was likely infectious in the Katherine and Darwin communities from Sunday until Tuesday. As a result, Katherine has been plunged into a 72-hour lockdown that started at midnight Friday. Under the lockdown, Katherine residents are only allowed to leave home for medical treatment, shopping for essential goods, performing essential work, exercising or providing care. Darwin residents who are fully vaccinated against Covid-19 are required to wear masks outdoors but can otherwise go about life as normal, while those who are not inoculated are subject to full lockdown restrictions. Anyone caught breaching the restrictions will receive a 5,000-Australian dollar (about 3,700 US dollars) fine. As of Wednesday, 77.8 per cent of people in the territory aged 16 and over had received one vaccine dose and 64.7 per cent were fully inoculated. "This is another reminder that the territory is absolutely vulnerable to Covid-19," Gunner said. "But you are more likely to catch Covid if you are unvaccinated, and you are way, way more likely to get seriously ill from Covid if you are unvaccinated." Victoria, New South Wales (NSW) and the Australian Capital Territory on Friday reported a total of 1,598 new locally-acquired coronavirus infections and 14 deaths. Meanwhile, Australia's most populated states, NSW and Victoria, reopened their shared border on Friday in recognition of their high Covid-19 vaccination rates. It means that for the first time in months, NSW travellers, including those who are unvaccinated, can cross the southern border into Victoria without quarantining or testing. They do, however, need to have an entry permit and prove they have not tested positive for the coronavirus. Fully vaccinated Victorians can now travel freely into NSW unless they have been to a region of the state with a high risk for virus transmission. Unvaccinated Victorians aged 16 and over still, however, are not allowed to cross the border. /IANS