The Indian Ocean archipelago of the Comoros has insisted it will not accept migrants expelled from the neighbouring French island of Mayotte.
It comes as authorities in Mayotte have pledged to launch Operation Wuambushu in which all migrants without official papers will be sent back to the Comoran island of Anjouan, 70km away.
Some, who gathered for Friday prayers, were hoping to stage a protest.
Resident, Mohamed Moindji, said: "I am very indignant at the reaction of our authorities. Because we are forbidden to demonstrate on Operation Wuambushu, an operation planned by France, the colonial power, to remove our brothers and sisters from their own land.
"There are people who would like to demonstrate their discontent, but the authorities forbid it. I really wonder if our authorities are there for us, if they are there to bring back the Comorian island of Mayotte."
Mayotte and the three islands of the present-day Comoros were French territories until 1975.
Following a referendum on independence, Grande Comore, Moheli and Anjouan islands declared themselves to be a separate country, the Union of the Comoros.
But Mayotte voted to remain a French overseas territory and later became a French department; a status rejected by the Comoros, which continues to claim the island.
Around half of Mayotte's roughly 350,000 population is thought to be foreign, most of them Comoran.
Officials in the capital Moroni had earlier urged Paris to drop the operation.
Government spokesperson, Houmed Msaidie, said: "This operation is clearly in contradiction with the spirit and the letter of the Convention that unites our two governments since July 2019.
"Consequently, the Comoros do not intend to welcome people expelled as part of the operation planned by the French government in Mayotte.
"The spirit and the letter of the Convention is to be set, to be set by both sides. And so to is the answering of the questions that arise in relation to the territories that we govern together."
Campaigners in Comoros have said Operation Wuambushu, which has been approved by French President Emmanuel Macron, was a "massacre waiting to happen."
Intense negotiations between Moroni and Paris have taken place in recent weeks, raising the possibility of a last-minute agreement.