The French interior minister, Gérald Darmanin, has met intelligence services to assess the terrorist threat to the country, after the Moscow concert hall attack claimed by Islamic State raised fresh security fears over the Paris Olympics. One of the biggest security challenges facing the organisers of the Games in the French capital is to protect the opening ceremony on 26 July. It is planned to be an unprecedented, open-air extravaganza, which for the first time in Olympic history will not take place within the confines of a stadium, but instead involve a flotilla of 94 boats carrying thousands of waving athletes down a 6km (3.7-mile) stretch of the Seine, followed by a further 80 boats carrying media and security, while an estimated 222,000 people gather along the river’s edge and 200,000 more watch from buildings. More than 45,000 police will be mobilised, with snipers on rooftops and elite officers poised on boats. Airspace will be shut down within a 150km radius around Paris during the ceremony, as the security services prepare for the potential threat of drone attacks. Darmanin has promised that French police and intelligence services will be ready for the extraordinary security operation and said that while the Games were an obvious future target for attacks, huge efforts and resources had been allocated to the wide-scale security and intelligence operations. “France, because we defend universal values, and are for secularism … is particularly threatened, notably during extraordinary events such as the Olympics,” Darmanin told reporters this week after the Moscow attack raised questions about a potential threat from abroad. “The French police, gendarmes, prefects, intelligence services, will be ready,” he added, saying that “we have a very effective intelligence system. We stop plots developing almost every month.” A poll by Elabe for BFMTV this week found that although 80% of French people were worried about terrorism, 59% were optimistic that France would successfully keep the Games secure. A total of 57% of French people thought the Olympics opening ceremony should go ahead in the open-air. French intelligence agencies are screening up to a million people before the Games, including athletes, staff, volunteers and people living close to key infrastructure, according to the interior ministry. After the Moscow attack on 22 March that killed at least 140 people, Paris upgraded its terror threat level to maximum – the country has in the past been a frequent target of jihadist attacks, including coordinated Islamic State attacks in Paris on the Bataclan concert hall, restaurants and the national sports stadium in November 2015. Emmanuel Macron said this week that the IS entity believed to be behind the Moscow attack – known as Khorasan, which is a branch in Afghanistan and Pakistan – had also sought to attack France. “This particular group made several attempts [at attacks] on our own soil,” the president told reporters. The prime minister, Gabriel Attal, said two planned attacks had been prevented in France since the start of the year. Earlier this month, Darmanin told a senate commission that the type of risk being assessed during the Olympics included the possibility of a move by a lone attacker inside France, or groups outside France paying criminals inside the country to stage an attack. He said there was no specific threat from a foreign group. “We can say today that groups such as al-Qaida or Islamic State have the intention to attack the west and France in particular, but they don’t have the means at the moment.” But, he added, intelligence was not a “precise science”. Céline Berthon, the French domestic intelligence chief, told the same senate commission that the terrorism risk had been increasing for more than a year. She spoke of “the return of an Islamist terrorism threat linked to external theatres, which we must not lose sight of, amid a tense geopolitical context with terrorist organisations who target the west and will no doubt, as the event approaches, seize the opportunity which the Games are”. There is also the potential for cyber-attacks during the Games, whether it be hackers targeting the stopwatch clocks at timed events or targeting broader computer systems or transport infrastructure. The head of France’s national cybersecurity agency told Agence France-Presse this week that the Paris Olympics would be a target, including for foreign states “that want to disrupt the Games because they are not happy for one reason or another, and who might try to disrupt the opening ceremony or cause problems on public transport”. The warning from Vincent Strubel, director general of the French Cybersecurity Agency (ANSSI), comes amid strained diplomatic relations between France and Russia over the war in Ukraine. Strubel told AFP: “Clearly, the Olympic Games are going to be a target. We are getting ready for all types of attacks – everything we see on a daily basis but bigger, more numerous and more frequent.”