“The two people came out, he shot at them, hitting one in the neck and the other in the chest and arm. He then fled.”

The victims, aged 74 and 78, were rushed to a nearby hospital with serious injuries, police said.

The man was tracked thanks to his number plate to his home town of Saint-Martin-de-Seignanx, a settlement of some 5,000 people just 16km from Bayonne, a popular tourist destination in France’s Basque country.

A source close to the investigation identified the man as Claude Sinke, and said he had admitted to being the gunman. He had also set fire to a car outside the mosque.

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Sinke had stood as a candidate for Marine Le Pen’s National Front in 2015 regional elections, according to the official list.

Macron said he “firmly condemns” what he termed a “heinous attack”, in a tweet Monday evening.

“The Republic will never tolerate hatred,” he said.

“Everything will be done to punish the perpetrators and protect our Muslim compatriots. I commit myself to it.”

Le Pen, for her part, labelled the attack “an unspeakable act”, and said it was “absolutely contrary to the values of our movement”.

Her National Rally said it had not been in contact with Sinke for months and said he was “no longer a member”.

Police said the man had three sub-military grade weapons, which he had declared to investigators.

The October 3 attack reignited a national debate about secularism, as a politician from Le Pen’s party asked a woman accompanying her son and other children on a school trip to remove her headscarf, describing it as an “Islamist provocation”.

Religion and extremism often get confounded in the ongoing debate as the country seeks to come to terms with a wave of jihadist attacks on its soil since 2015.

Dozens of mosques were targeted by arsonists, but also with firebombs, grenades or even gunfire, after the first in a series of attacks by Islamist radicals - that of 12 people at the Charlie Hebdo satirical magazine.

But Muslim sites were intermittently targeted even before then.

In 2007, 148 Muslim headstones in a national military cemetery near Arras were smeared with anti-Islamic slurs and a pig’s head was placed among them.

In March this year, workers building a mosque in the small southwestern town of Bergerac found a pig’s head and animal blood at the entrance to the site -- two weeks after a gunman killed 50 Muslims in Christchurch, New Zealand, in a shooting spree at two mosques.

CFCM leader Abdallah Zekri said there was “a great deal of concern” among France’s Muslims, adding attacks like the one on Monday were “not surprising given the climate of stigmatisation of Islam and Muslims”.

Additional reporting by DPA