Islam can co-exist with secularism, President Francois Hollande said Thursday, warning in a speech seen as preparing the ground for a re-election bid that the anti-terror fight should not undermine French values.

The deeply unpopular Hollande has yet to announce whether he will run for a second term next year, but is widely expected to be a candidate.

In a passionate plea for tolerance, he defended the country's Muslim minority following a vitriolic debate on the banning of the Islamic burkini swimsuit.

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Ill fated reign: During his presidential tenure Hollande has seen a number of terror attacks including the deadly assault in Paris last November and the Nice lorry attack in July. A survey conducted by pollster TNS Sofres said 90% of the French public disapprove of their president

'Nothing in the idea of secularism opposes the practice of Islam in France, provided it respects the law,' Hollande said.

Secularism was not a 'state religion' to be used against other religions, he said in the speech in Paris, denouncing the 'stigmatisation of Muslims'.

Mayors in around 30 towns this summer cited France's century-old secular laws in banning head-to-toe swimwear on their beaches, unleashing a furore.

Several of the towns later revoked the bans after France's highest administrative court ruled they were a 'serious' violation of basic freedoms.

Hollande rejected calls by conservatives, including his arch-rival, former president Nicolas Sarkozy, for the state to ban the burkini, saying it would be 'unconstitutional'.

A Burkini wearer on a beach in Marseille in August (far left). Bans on wearing the concealing beach wear were overturned towards the end of last month. The ensuing debate on the ban revealed raw tensions between the secular establishment and sectors of France's estimated 5 million Muslims

Asking whether Islam could co-exist with secularism, like Christianity and Judaism, he insisted: 'My answer is yes, certainly.'

'The question the Republic must answer is: Is it really ready to embrace a religion that it did not expect to be this big over a century ago? There too, my answer is yes, certainly.'

In a wide-ranging address Hollande cast himself as a guardian of democracy, resisting calls for more repressive laws following a string of jihadist attacks that have left over 230 people dead in France since January 2015.

The authorities this week launched another anti-terror investigation, following the discovery of six gas cylinders in an abandoned car near Paris' Notre Dame cathedral.

Seven people are being held over the find, which comes two months after a Tunisian radical slammed a lorry into a crowd of Bastille Day revellers in Nice, killing 86 people.

Hollande said attack plots had been foiled 'in recent days' but did not elaborate.

Protesters constructed a temporary 'beach' outside the French Embassy in London last month to vent their anger at the controversial burkini ban across the channel

The government has responded to the threat by deploying thousands of troops to patrol the streets, enacting a raft of anti-terror laws and repeatedly extending a state of emergency - measures deemed insufficient by the conservative opposition.

Sarkozy, who has announced a bid to try to win back the presidency in next year's election, has called for suspected radicals to be interned in camps.

The former president responded late Thursday to Hollande's comments, saying that 'democracy can't be weak. We are France, we cannot accept impotence.'

Sarkozy, putting himself forward as a strong contrast to Hollande, added; 'I want to be president of a Republic which will protect the French people and which will defend France.'

Hollande warned that France could not sacrifice its core values of liberty, equality and fraternity.

'The declaration of human rights is not some old scroll to be framed and hung in reception rooms,' he said.

'Did the Patriot Act and Guantanamo protect Americans from the (terrorist) threat? No,' he said, declaring: 'Democracy is our weapon.'

Polls predict a drubbing for the 62-year-old Socialist if he throws his hat in the ring again after five years marked by stubbornly high unemployment and only timid attempts at reform.

Hollande has deferred his decision on whether to run until December.

A poll published Tuesday showed he would only get between 11 and 15 percent in the first round of voting.

A separate survey for BFMTV Wednesday showed 88 percent of the French opposed to Hollande standing again.

Three of Hollande's former ministers have already announced their own presidential bids.

They could soon be joined by ambitious former economy minister Emmanuel Macron, who resigned from government last week.

Despite his own camp being in disarray Hollande has cast himself as a unifying force at the helm of the state.

'When there is danger we must come together,' he said.