TORONTO -- The chief of a northwestern Ontario First Nation says all families and children have been evacuated from the community, just days after an oily sheen was discovered in the Neskantaga water reservoir.

Neskantaga First Nation Chief Christopher Moonias made the announcement in a social media post late Saturday night, adding that 24 people remain on the ground to look after the community.

Those who fled the community were brought to Thunder Bay, Ont., more than 400 kilometres away.

Initially only those deemed vulnerable were evacuated, but as the situation developed the chief called on everyone in the region to flee.

The contamination, which was discovered on Tuesday, has prompted officials to shutdown the water plant. Initial test results revealed high levels of hydrocarbons in the water supply, which serves roughly 400 people in the region.

“Monday morning I will be flying back to the community with Matawa and NAN Tech Services, ISC community infrastructure reps, local reps to go inspect the Water Treatment Plant,” Moonias said in a tweet.

Indigenous Services Canada has said it would provide funding for evacuation efforts, however, Minister Marc Miller has not yet provided any specific details.

“I am deeply concerned by the shutdown of Neskantaga’s water distribution system and resulting health emergency,” the minister said in a tweet on Oct. 21 “Safe, clean and reliable drinking water is an essential service, one that has not been afforded to Neskantaga in over 25 years. This is entirely unacceptable.”

The minister says the federal government is funding $16.44 million for a new water treatment plant and upgrades to the water distribution and wastewater collection systems.

He added, “I will work with Chief Moonias and Neskantaga on a long-term solution to restore potable water and offer my full support for immediate interim measures.”

Neskantaga holds the country’s longest-running boil water advisory, which has been in place for 25 years.

With files from The Canadian Press.