MORONI, Comoros (CNN) -- Witnesses reported looting and summary executions on the Cormoran island of Anjouan on Tuesday, three days after an assassination attempt led to open warfare between the island's rival separatist groups.

Diplomats on the main Comoros island of Grand Comore said a militia faction loyal to politician Chamassi Said Omar seized control of Anjouan's capital, Mutsamudu, late Monday. Residents said they saw heavily-armed militiamen carrying out executions of civilians on the streets.

"Their real aim is to entirely destroy Mutsamudu," Mohamed Abdou, a local shopkeeper, said by telephone on Monday.

The Comoran government said it had sent a ship from Grand Comore to evacuate dozens of children from the island in the Indian Ocean nation, off the east coast of Africa.

Omar is demanding the resignation of the island's secessionist president, Foundi Abdallah Ibrahim, who escaped a second assassination attempt in just over a week on Saturday.

The advancing militia is loyal to Omar. The opposing sides both want independence for Anjouan, but they disagree on whether the island should try to rejoin France. Comoros achieved independence from France in 1975.

Foundi led the secession movement on the islands of Anjouan and Moheli last year, saying mismanagement by political leaders on Grand Comore had brought poverty and political chaos. Chamassi supports the islands' reattachment to France, which has refused to support the secessionist movement.

Chamassi fled to the French-ruled island of Mayotte on Sunday to lead the uprising from there. Foundi's whereabouts were unknown Tuesday.

Residents said between 40 and 60 people had been killed in machine gun and artillery battles which exploded on Saturday. Fighting resumed early Monday after a short-lived cease-fire.

The Organization of African Unity on Monday appealed to the warring parties to end the fighting and called on the countries of the region to respond "positively" to the request of the Comoran government for assistance in restoring peace.