French police say they have foiled an “imminent” terror attack ahead of the country’s national elections after finding a machine gun, two hand guns and three kilograms of explosives in a raid on a Marseille flat.

Paris prosecutor Francois Molins told a news conference Wednesday morning that two men, known to have turned to radical Islam, were arrested over the plot.

Mr Molins said an Islamic State flag and jihadist propaganda had previously been found at the home of one of the men, while the other was thought to have had links to a Belgian jihadist cell.

The suspects, Mahiedine Merabet, 29 and Clement Baur, 23, allegedly “intended to commit an attack on French soil in the very short term, which is to say in coming days,” Interior Minister Matthias Fekl said during a media conference.

France heads to the polls on Sunday in the first round of its two-stage national election.

The men, both French nationals, are “suspected of wanting to commit, in an imminent way, a violent action on the eve of the French presidential election”, the minister said.

Fekl did not elaborate on potential targets or motives for the alleged plot.

He said Agents from the French domestic security agency, backed by elite police units, conducted the arrests and further searches were also underway.

Extra measures are being put in place to ensure for the polling as France’s fight against homegrown and overseas Islamic extremism emerged as one of the main campaign topics for presidential candidates.

Candidates on the far right have used their campaigns to appeal to voters traumatised by IS-inspired attacks that have killed at least 235 people in France since January 2015, the largest casualty rate of any Western country.

Merabet and Baur were detained for terrorist criminal association, according to a police document obtained by The Associated Press.

President Francois Hollande hailed the “remarkable” arrests and the work of police.

– With agencies