HONG KONG (AP) — Hong Kong leader Carrie Lam on Tuesday urged residents to stay home as the city grapples with a resurgence of the coronavirus, which has infected more than 600 people in the last week.

Lam asked citizens to “refrain from social gatherings” and said that people, in particular the elderly, should remain at home.

“The latest wave of the epidemic is rather severe. Every one of us should do our best and exercise a high level of discipline to fight the pandemic,” she said at a regular news conference. “The coming two weeks is a crucial period.”

The city reported 82 new infections on Tuesday, 23 of which were unlinked to known clusters. Hong Kong has reported 6,397 infections since the pandemic began, with 109 deaths.

Many of the new infections in Hong Kong have been tied to dance studios, and outbreaks have also been found among staff and guests at several restaurants. The new uptick in infections follows a more than three month period during which Hong Kong reported just a handful of cases each day.

Authorities have responded by tightening social distancing restrictions, including closing entertainment venues such as karaoke bars and game centers and limiting public gatherings to two people. A hotline has been set up to allow the public to report large gatherings on yachts.

The growing number of cases has further delayed a “travel bubble” between Singapore and Hong Kong that was initially slated for November. The bubble would have allowed visitors to travel between the cities without needing to quarantine if they tested negative for the coronavirus.

Statements by the Hong Kong government and Singapore’s civil aviation authority on Tuesday said both cities have decided to postpone the bubble beyond December, given the high number of local cases in Hong Kong.