French secondary schools held a minute’s silence on Monday after a teacher was killed by a former pupil in what the government called an Islamist terror attack, prompting Emmanuel Macron to call for a “ruthless” approach towards extremists. France has been placed on its highest level of security alert after a 20-year-old terrorist suspect who had been under surveillance walked into his old high school in Arras, northern France, on Friday and stabbed to death a French teacher, Dominique Bernard, and injured three others. The 57-year-old teacher died from several wounds to the neck. The attack – which happened almost exactly three years after Samuel Paty, a 47-year-old history and geography teacher, was killed by an 18-year-old Chechen man outside his school near Paris – has triggered a massive security response and questions from teachers over whether schools in France are safe. At 2pm, all schools across France observed a minute’s silence. The Gambetta-Carnot high school in Arras, where the attack happened, was evacuated on Monday morning after a bomb alert. Police explosive experts arrived at the site as teachers and students were given psychological support before being allowed back into the building. The 20-year-old suspect, who was arrested at the scene, remained in police custody on Monday, and French media reported that he was not answering investigators’ questions. Police named him as Mohammed Moguchkov, who was born in Russia’s predominantly Muslim North Caucasus republic of Ingushetia and reportedly arrived in France at the age of five. He was on a French national register as a potential security threat and under electronic and physical surveillance by France’s domestic intelligence agency, the DGSI. His father, who was also on the list, was deported in 2018. Macron said he wanted his ministers “to embody a ruthless state towards all those who harbour hate and terrorist ideologies”, a senior aide told reporters. The president has called on police to comb through their files of radicalised people who could be deported from France to make sure no one has been overlooked. Macron had told his interior minister to take a “special approach to young men between the ages of 16 and 25 from the Caucasus”, AFP reported. The killing of a teacher inside a school has increased nervousness over security in France, which has large Muslim and Jewish populations and has been on the alert for violence since the attacks on Israel on 7 October. The prime minister, Élisabeth Borne, said on Monday: “We will not allow terrorism to bring our country to a standstill”. Borne told La Tribune Dimanche this weekend that, although the investigation into the school killing was ongoing, “the attack against Israel could have been a trigger element”. The interior minister, Gérald Darmanin, said there was “an atmosphere of jihadism” in France since the Hamas attack on Israel and the ensuing bombardment of Gaza. At the weekend, the Louvre museum, the palace of Versailles and the Gare de Lyon station in Paris were evacuated after a series of bomb alerts, but Darmanin said there had been no genuine threat. France has increased security around schools and Jewish sites, increasing the number of troops on patrol to 7,000. In a post on X, formerly Twitter, Macron said French schools would remain a “bulwark” against extremism and “a sanctuary for our pupils and everyone who works there”. With two hours of morning lessons across all French secondary schools cancelled on Monday in order for teachers to discuss how to deal with the attack and increased threat, some teachers’ representatives said the opposite was happening. Iannis Roder, a history and geography teacher in a middle school in Seine-Saint-Denis, told France Inter radio he felt schools were no longer a sanctuary and in fact were a “target”. The Arras attack has also sparked a fresh row over immigration before the government’s new bill on the issue, scheduled for the new year. There had been criticism from figures on the right who are against allowing a regularisation process for some migrants without residence permits working in specific jobs. The focus of debate is on increasing means to expel more people. Jordan Bardella, of Marine Le Pen’s far-right National Rally party, said the Arras attacker’s family “should not have been on French territory”. The head of the lower house of parliament, Yaël Braun-Pivet, who belongs to Macron’s centrist Renaissance party, said on Monday that a draft immigration law should be sped up and voted through by the end of the year. She said the bill would provide that “people who are not integrated, who are radicalised, who swear ferocious hatred against the (French) republic … must indeed be able to be removed”, she told the public broadcaster France 2.