New Zealand’s first coronavirus outbreak in six months has grown to seven people, AP reports.

The announcement on Wednesday came a day after Prime Minister Jacinda Ardern imposed a strict lockdown after the first case was reported. The lockdown is for at least three days for the country and at least a week for the cities of Auckland and Coromandel.

Ardern says genome testing has confirmed the outbreak is of the Delta variant and originated from an outbreak in Sydney, Australia, although it’s not yet clear how the virus breached New Zealand’s border quarantine controls.