Poland has deployed more than 20,000 police officers nationwide following a series of school stabbings and online threats, launching a sweeping security crackdown that has resulted in dozens of arrests.

The emergency measures follow three stabbing attacks in four days that left one person dead and more than a dozen injured. Threats of further violence circulating online have fueled widespread alarm, prompting some schools to suspend classes and parents to keep their children at home.

Police announced on Monday that officers conducted nearly 80,000 inspections of educational institutions, detained 135 people, and identified 311 suspected criminal offenses.

“Police operations are still underway throughout Poland to ensure the safety of children, young people, and all employees of educational institutions,” the national police headquarters said, adding that officers are monitoring online threats around the clock.

Interior Minister Marcin Kierwinski ordered the nationwide operation on Sunday, stepping up patrols inside and around schools. He confirmed that 24,000 officers have been mobilized.

“There will be no tolerance for any attacks on Polish children, nor for the descent of public life into anarchy,” Kierwinski told state broadcaster TVP Info.

Police have also detained teenagers suspected of planning attacks or posting violent threats online.

In one case, investigators discovered that a boy had recreated his school in the online game Roblox and simulated attacks on fellow students. Police said they found a firearm, ammunition, and knives in his possession.

The security operation follows three stabbing incidents in less than a week.

On Wednesday, a 19-year-old attacked students, teachers, and passersby at a vocational school in Ostroleka, north of Warsaw, injuring nine people before being arrested.

The following day, a 15-year-old former pupil wearing a helmet-mounted camera fatally stabbed a school caretaker and wounded two teachers in Leszczydol-Nowiny, northeast of the capital.

On Saturday, three people were injured in another stabbing at a further education college in Warsaw. A woman was detained in connection with the attack.

The violence was followed by a surge in social media threats of a ‘Bloody Friday’ campaign targeting schools, further fueling public fears.

Prime Minister Donald Tusk has warned of a growing “fascination with violence” among young people, describing it as a disturbing trend both in Poland and worldwide.

The authorities, however, said investigators found no evidence that the attacks were coordinated, warning that misinformation and unverified threats circulating online contributed to public panic.