Five days before the first round of France’s presidential election, two men have been arrested on suspicion of planning an imminent attack,
The suspects, aged 23 and 29, were detained in Marseille by elite police and domestic intelligence agents after a search that had lasted several days.
Both men were said to have been radicalised in prison.
France remains under a state of emergency after a series of attacks that have claimed some 230 lives.
A flat in the rue de Crimée in Marseille’s central third district was being searched amid reports that guns and material used for making explosives had been found. Neither man was from Marseille.
They were named as Mahiedine M, 29, and from Croix near the Belgian border, and Clément B, aged 23 and from Ermont, north of Paris.
Interior Minister Matthias Fekl did not say what the suspects’ target was. He described the men as French.
“They had the aim of committing in the very short term, in other words in the very next days, an attack on French soil,” he said.
The DGSI domestic intelligence service is said to suspect the pair of plotting an attack to coincide with the election. The men were being held as part of an inquiry into “criminal terrorist association and violating the law on arms relating to a terrorist enterprise”.
One of the main election candidates, Francois Fillon, was warned of “confirmed risks” late last week, French media report.
Photos of the suspects were circulated to security officers looking after election front-runners Marine Le Pen and Emmanuel Macron, AFP news agency said.
Eleven candidates will contest the first round on 23 April, with the top two qualifying for the run-off on 7 May.
The interior minister said 50,000 members of the security forces were being deployed for the elections.
President Francois Hollande praised the Marseille operation, which began after 10:00 (08:00 GMT).
Although no major attack has been carried out on French soil in recent months, two soldiers were attacked with machetes outside the Louvre museum in Paris in February. In the same month, three men and a 16-year-old girl were detained in Montpellier on suspicion of planning a bomb attack.
France has been under a state of emergency since the Paris attacks in November 2015 and officials say the risk is still very high, pointing to recent murders in the UK and Sweden.
On 22 March, Khalid Masood killed five people in London when he drove into pedestrians on Westminster Bridge and stabbed PC Keith Palmer outside Parliament.
On 7 April, Rakhmat Akilov, 39, drove a lorry into a Stockholm department store, leaving four people dead.