A mum and two kids were rushed to hospital after it was suspected they had been poisoned.
The 38-year-old woman and two children, aged nine and 13, were discovered at an address in Uckfield, East Sussex.
It is not known what condition they were in when they were discovered.
The trio, who were found at the address in Hunters Way, were taken to hospital where currently remain today.
Emergency services were called to Hunters Way
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Now, Sussex Police has confirmed a woman has been arrested on suspicion of administering a noxious substance/poison to cause injury.
The Sun reports that the three remain in hospital today. It is believed that they are in a stable condition.
Sussex Police has now confirmed that the incident is being treated as isolated.
However, officers are expected to remain in the area for the rest of the day while an investigation is ongoing.
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Emergency services were called to the scene (file pic)
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A spokesperson from Sussex Police said: “While their conditions remain serious, they are currently in a stable state. A woman has been arrested on suspicion of administering a noxious substance / poison to cause injury.
"We are not searching for anyone else in relation to this investigation.
"Our enquiries are ongoing and a heightened police presence is anticipated in the area at this time.
"This is being treated as an isolated incident with no threat to the wider community.”
Councillor for the town’s north ward Dan Manvell told The Independent: "It is obviously something which doesn’t usually happen in Uckfield. Nothing more than low level antisocial behaviour occurs here, so this is worrying.
"It looks like an isolated incident but I’m sure it is upsetting for all those involved, including the family. I hope they get better soon."
One person said of the incident: "Very sad. I hope the children are as well as can be with something so traumatic."