Five people were in custody in Kosovo on Sunday, suspected of a terrorist plot to contaminate the water supply in the capital, Pristina, after exhortations on recent videos released by the Islamic State to poison the country’s food and water supplies.

Local news reports said that three people were arrested early Saturday morning while acting suspiciously in the vicinity of the Badovac reservoir, which supplies Pristina with nearly half its water. Weapons, ammunition and Islamic State propaganda were found in the suspects’ two Volkswagens, the reports said.

Two more people were arrested later in Pristina and charged with terrorism in connection with the suspected plot, Kosovo officials said.

Two of the suspects had also been arrested last year on suspicion of traveling to Syria, Reuters reported, citing an unidentified police source.

Pristina water officials decided to cut off water to tens of thousands of the capital’s residents on Saturday morning until tests could be conducted to determine whether the water had been contaminated. At first, Kosovo officials attributed the cutoff only to “security issues,” but they later said it was linked to the suspected poisoning plot.

By Saturday evening, government health officials said tests had concluded that the water was not tainted and urged the city to restore service.

In the recent Islamic State videos, a man can be heard urging just such a plot, Reuters reported.

“If you can, take poison and put it in their meal or in their drink,” the man is heard saying. “Make them die, make them die of poisoning, kill them wherever you are.”