Thirty people were missing Thursday after a boat carrying them from the Comoros broke up in rough seas on its way towards the French Indian Ocean island Mayotte, French officials said.

Eleven people were rescued from the large dug-out canoe that went down on Monday while carrying Comorans hoping to illegally enter French territory.

The survivors -- who include a pregnant woman, two teenagers and a people-smuggler -- had clung to pieces of the canoe after the vessel split in two in heavy seas, said the officials in the Mayotte capital Mamoudzou.

They were spotted by a fishing vessel which alerted authorities in Mayotte, which lies between northern Madagascar and northern Mozambique off the east coast of Africa.

The Comoros archipelago has seen frequent coups since independence from France and is far poorer than Mayotte, whose relative wealth makes it a magnet for illegal migrants who make a perilous boat journey there.

Around 40 percent of the 200,000 residents of Mayotte are believed to be living there illegally. Last year French authorities shipped 16,000 Comorans back home.

The people of Mayotte this year voted for their island to become a department of France, and by 2011 they will enjoy full voting and citizenship rights.

In 1974 Mayotte became a French-ruled "collectivity" while the other islands in its archipelago chose independence as the Comoros.

The current Comoros leadership has condemned the referendum this year on joining France and declared Mayotte "occupied territory."