Australia’s most populous state New South Wales called on residents in three cities to be tested for Covid-19 and isolate, as concerns grew that a Sydney cluster may have spread to regional areas after a visitor from the city tested positive.

New South Wales state, the epicentre of Australia’s latest outbreak, said it had detected four new local cases of Covid-19 in the past 24 hours, one in a man who travelled from Sydney to the outback town of Broken Hill, Reuters reported.

“This is a reminder of what can occur for people who are moving out of Sydney. We said clearly in the past, if you have any symptoms, if you are concerned, you should limit your mobility,” acting NSW Premier John Barilaro told reporters in Sydney.

Barilaro urged people in three regional NSW cities, which the infected man visited, to get a Covid-19 test and isolate while awaiting a test.