Prime Minister Donald Tusk said on Monday that about 20,000 police officers were patrolling schools and their surroundings across the country.
Ten schools were closed for the day, nine in the central Mazowieckie province and one in Kujawsko-Pomorskie in north-central Poland.
The measures were introduced after three acts of violence at schools in the Mazowieckie region last week.
Schools and preschools have been under additional police supervision since Friday, with municipal guards supporting the operation.
"As long as we continue to see situations that cause concern, schools will remain under this special supervision so that they are fully safe places," Tusk said after a government security meeting on Monday.
Interior Minister Marcin Kierwiński said the increased patrols would continue for at least several more days and could be extended or intensified if necessary.
Police said that by 6 a.m. on Monday they had recorded 311 incidents, detained 135 people and checked nearly 80,000 educationa l institutions since the operation began.
Tusk said a further 18 people were detained and checked on Monday. Authorities are also monitoring the internet around the clock.
Kierwiński said the Central Bureau for Combating Cybercrime (CBZC), Poland’s specialized police unit dealing with online crime, was seeing the situation begin to stabilize.
Monday was "considerably calmer" than Friday, he said.
Photo: PAP/Przemysław Piątkowski
National Police Commander Marek Boroń also reported a decline in the number of online posts referring to possible threats against schools.
Digital Affairs Minister Krzysztof Gawkowski has called an emergency meeting for Friday with representatives of Meta, Google, TikTok, Discord and Telegram.
He said the government would present monitoring data and ask the platforms to remove dangerous material as quickly as possible.
Authorities have identified copycat accounts, repeated threatening material and content glorifying a killer, Gawkowski said.
Officials have also seen signs of extremist groups reinforcing one another online.
Gawkowski said the recent school attacks were also being used to spread disinformation, with Russian bot activity detected since Sunday.
However, Poland’s Internal Security Agency (ABW) has said it has found no evidence that the wave of school-related incidents was directed from abroad.
ABW deputy head Adam Ciszewski said information received by the agency was being checked with security services in other countries.
The agency continued to assess the events late last week as "spontaneous, decentralized and not controlled from outside," he said.
Polish police on Friday stepped up patrols and tightened security around schools nationwide after recent knife attacks. Photo: PAP/Marcin Obara
Tomasz Siemoniak, the minister coordinating Poland's security services, said the ABW had meanwhile recorded a sharp decline in Russian bot activity online.
Education Minister Barbara Nowacka said schools had received guidance on how teachers should respond to threats involving dangerous weapons or other objects.
She stressed that teachers should not be expected to act as security personnel.
"Teachers are not guards. They are people who are there to teach children and support their upbringing," Nowacka said.
Health Minister Jolanta Sobierańska-Grenda said calls to the 116 111 child and youth helpline had risen by 40 percent since Friday, although the number had since begun to stabilize.
The health and education ministries are also preparing webinars for teachers with psychiatric specialists on how to respond to dangerous situations and provide appropriate support.
Last Thursday, a 15-year-old former student attacked three people with a knife at a primary school in the village of Leszczydół-Nowiny, near the town of Wyszków, about 50 km northeast of Warsaw, killing a 37-year-old school employee and injuring two others.
A day earlier, a 19-year-old attacked schoolmates and teachers at a vocational school in Ostrołęka, 120 km northeast of the capital, injuring five students, two teachers and two other people.
Prosecutors said the suspect also attempted to detonate a homemade explosive device at the school.
Also on Wednesday, police in the town of Sierpc, 125 km northwest of Warsaw, foiled a planned school attack and detained a 17-year-old who had told classmates he planned to "do something bad at school," according to authorities.
(rt/gs)
Source: IAR/PAP, TVP Info, TVN24