Turkish authorities detained at least 17 people in several provinces and jailed multiple suspects over online threats of school attacks and posts praising violence after Turkey’s first fatal school shooting left 10 people dead in southern Kahramanmaraş province.

The reported cases included seven students detained in the northern province of Samsun, two people detained in the western province of Denizli and separate detentions or arrests in İstanbul, Sivas, Zonguldak, Çanakkale, Kırşehir, Tokat, Bolu and Antalya.

The Samsun Governor’s Office said cybercrime police opened an investigation after posts circulated online claiming schools in the province could be targeted, according to the state-run Anadolu news agency. Six of the detained students were under 18 and were taken into custody by juvenile police, while a seventh, who was over 18, was detained in the Atakum district. All seven were referred to court after police questioning.

In İstanbul a high school student was detained following reports that he had shared a bomb photo on Telegram and posted messages saying he would carry out a bombing tied to the Kahramanmaraş attack. Turkish media reported that police found a tactical vest, camouflage clothing, a helmet, a knife and pepper spray during a search of the student’s home. The student was later jailed pending trial.

In Denizli, two people were detained over posts about possible similar attacks in the city. The governor’s office said one was detained on suspicion of threatening to create fear and panic among the public and the other on suspicion of praising crime and criminals. In Sivas, a 17-year-old, 10th-grade student was detained and later jailed over a post suggesting schools in the province could be attacked.

Other cases were reported across the country. A 17-year-old high school student was detained in Zonguldak after allegedly posting messages in a class WhatsApp group saying he would attack his school; police reportedly found six blank cartridges at his home. A 14-year-old student was detained in Çanakkale’s Ezine district after allegedly posting a threat on social media. Three people were detained in Kırşehir, one student was jailed in Tokat, one student was detained in Bolu over an alleged voice recording about shooting a school principal and classmates, and two students were detained in Antalya over messages saying they would bring guns to their school.

The specific cases came as police announced a broader nationwide crackdown on posts linked to school attacks in Şanlıurfa and Kahramanmaraş. The police said 411 people had been detained, 307 account administrators had been identified over posts described as misleading, threatening or inciting, 1,866 internet addresses had been blocked and 111 Telegram channels linked to a group called “C31K” had been shut down.

The detentions came as Turkey remained shaken by the attack Wednesday at Ayser Çalık Middle School in the Onikişubat district of Kahramanmaraş province. Authorities said a 14-year-old student, identified by Turkish media as İsa A.M., opened fire at the school, killing eight students and one teacher and injuring 12 more before being stabbed in the leg by the father of two children who attended the school. The attacker reportedly died of his injury.

The Kahramanmaraş Governor’s Office said Friday that eight students wounded in the attack were still being treated at a hospital and that five of them were in intensive care.

Authorities have not announced a motive. Turkish media reports and online material attributed to the assailant have pointed to an interest in violent internet subcultures and past mass attackers, though those claims have not been independently verified. The reports have added to concern that the shooting may have been driven not by a local political or criminal dispute but by online communities that glorify violence and encourage alienated teenagers to imitate previous attackers.

The attack has also raised questions about how the teenage assailant obtained a firearm and weapons training, given that gun ownership is heavily regulated in Turkey. The Kahramanmaraş Governor’s Office said the boy had visited a police shooting range with his father, Uğur Mersinli, a senior police chief, on April 13, three days before the attack, and fired shots there. An officer identified as M.Y., who was on duty at the range, was suspended, and Turkey’s police inspection board opened an investigation into officials who may have shared responsibility.

Mersinli, whose guns and ammunition were allegedly used by his son in the attack, was arrested after the shooting.

Local authorities also decided to keep Ayser Çalık Middle School closed beyond an initial two-day suspension, the Cumhuriyet newspaper reported, citing governor’s office sources. Students are expected to be transferred temporarily to nearby schools starting Monday, sparing them from returning to the site of the attack while they are still dealing with the trauma.

Parents told Cumhuriyet they supported the decision, saying their children remained shaken by the shooting and by images of students jumping from windows to escape.

The Kahramanmaraş attack was Turkey’s first fatal school shooting and came a day after a separate school shooting was reported in Siverek in the southeastern province of Şanlıurfa. The back-to-back incidents have intensified concern over minors’ access to firearms, online threats and violent digital subcultures among teenagers.