SKOPJE, Republic of North Macedonia (AFP) — More than 1,000 people have been treated for poisoning symptoms in North Macedonia, a hospital said Friday, after contaminated river water was allegedly pumped directly into a town’s drinking supply.

Although the hospital in the town of Gostivar — about 50 kilometers southwest of the capital Skopje — did not confirm a direct cause, it said it had treated a large number of people with vomiting, diarrhea and stomach pain over the past four days.

Police were investigating the cause but believed the local water company may have pumped wastewater directly into the town’s water supply.

The local force said in a statement the idea was most likely to increase the supply of drinking water — the area regularly suffers from shortages during the summer.

Authorities have temporarily banned drinking from the town’s supply, and the hospital has boosted staff to manage the influx of sick people.