The soldiers sailed on board two ships they seized on Monday. The captains of the ships had originally refused to sail overnight. Comoran authorities earlier told an envoy of the Organisation of African Unity (OAU) that the troops at Moroni port were simply going on manoeuvres.
But speculation about a military intervention has grown on Grande Comore, largest of the three-island group in the Indian Ocean that forms the Federal Islamic Republic of the Comoros.
Some passengers said they had seen the deployment of heavy weapons on the island by secessionists. They reported ordinary people as being in a festive mood in Mutsamudu, Anjouan's main town. "Many people are singing and dancing in the streets of Mutsamudu ... they seem eager to fight the Comoran army," one passenger said.