MONTREAL -- Montreal mayor Valerie Plante announced on Thursday that the city would close all public sports and leisure centres in an effort to prevent the spread of COVID-19.

The mayor said libraries, pools, arenas, community centres and other city installations where people gather in large numbers would be closed, including the Planetarium and the Claude-Robillard complex. The closures will begin to take place Thursday evening, Plante said, starting with the largest centres.

"All the installations, we'll close them down until we take a new decision," Plante said, noting that Premier Francois Legault said earlier on Wednesday that all gatherings of 250 people or more should be cancelled. "In Montreal [all centres] are around 250 people that's a pretty easy decision to reach. ... Ultimately if it's 200 people, we're still going to close it."

Organizers of major public events, including the St. Patrick's parade, have cancelled or postponed them.

The Montreal Metro system, however, will remain open, Plante said, because it is vital to the function of the city.

Public servants working for the city who have returned from travel outside of Canada have been asked to self-quarantine, regardless of their destination, Plante said.

Quebec currently has 13 cases of COVID-19. All of those people likely contracted the virus abroad, but health officials warn that the localized transmission of the virus is inevitable. Another 266 people are under investigation for the virus.

Those who have travelled abroad and experience symptoms that could be associated with the virus: fever, coughing, difficulty breathing, have been asked to call 811, but that line has been bombarded and wait times are long. Health officials are currently only testing those who have symptoms and have returned from trips to virus hotspots.