A new open letter has been published in France warning of the threat of civil war and claiming to have more than 130,000 signatures from the public.

The message, published in a right-wing magazine, accuses the French government of granting "concessions" to Islamism.

"It is about the survival of our country," said the text, said to be issued anonymously by soldiers and appealing for public support.

The French government condemned it, as well as a similar letter last month.

Interior Minister Gérald Darmanin called the latest letter a "crude manoeuvre" and accused its anonymous signatories of lacking "courage", AFP news agency reported.

The letter to the government last month came from semi-retired generals. The minister in charge of the armed forces, Florence Parly, said they would be punished for defying a law that forbids reservists or serving members of the military from expressing opinions in public on religion and politics.

However, far-right leader Marine Le Pen, a candidate in next year's presidential election, spoke out in support of the estimated 1,000 servicemen and women who backed the April letter.

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The new text was published late on Sunday by Valeurs Actuelles, although the numbers and ranks of its original signatories - said to be active members of the military - remain unclear.

The authors of the letter describe themselves as part of a younger generation of soldiers who have served in Afghanistan, Mali and the Central African Republic, or joined domestic anti-terrorism operations.

"They gave their skin to destroy the Islamism to which you are giving concessions on our soil," they wrote.

Step into the unknown
Analysis box by Hugh Schofield, Paris correspondent

Because of their anonymity, it is impossible to gauge how far the writers of this new letter represent the rank-and-file of the armed forces. Online petitions where no-one has to give their name cannot be regarded as firm evidence of anything.

Nonetheless, it would come as no surprise if this kind of generalised pessimism about the state of France were indeed the commonplace of barrack-rooms and officers' messes the length and breadth of the country.

Most French civilians are also concerned about violence, drugs and Islamism, so for soldiers - by instinct more attached than most to tradition, law-and-order and authority - to share those views is hardly in itself of note.

What's contentious is the willingness to go public and blur the lines between the military and the political. And on that score there will be many in the armed forces who disagree with the letter-writers. The analysis - even the warnings of disintegration and civil war - may be widely shared.

But urging politicians to "act" to stop the rot, with an implicit "or else" if they don't: that is a step into the unknown that the people who count in the armed forces - the top brass - would certainly not condone.

The new message criticised the French government's response to the "elders" who signed last month's letter: "Did they fight for you to allow France to become a failed state?"

"If a civil war breaks out, the army will maintain order on its own soil," the letter went on to say.

"No one can want such a terrible situation - our elders no more than us - but yes, civil war is brewing in France and you know it perfectly well."

France has recently proposed a controversial bill to tackle what President Emmanuel Macron has described as "Islamist separatism".

However, some critics in both France and abroad have accused the government of unfairly targeting Islam.