New Zealand announced its first locally transmitted coronavirus infections in 102 days on Tuesday, prompting the country’s prime minister to issue a stay-at-home lockdown order for the country’s largest city.

Jacinda Ardern said four cases had been detected in a single family in Auckland from an unknown source.

“After 102 days, we have our first cases of COVID-19 outside of managed isolation or quarantine facilities… While we have all worked incredibly hard to prevent this scenario, we have also planned and prepared for it,” she said.

New Zealand had declared itself coronavirus-free on June 8 after the country’s final patient was given the all clear and released from isolation.

The milestone was “really good news” and an achievement the whole of New Zealand could take heart from, health department director-general Ashley Bloomfield said.

New Zealand had won praise for its handling of the pandemic, which involved a strict seven-week lockdown that ended in May after the virus was contained.