By Ahmed Ali Amir MORONI, Nov 5 (Reuters) - The African Union has begun a naval blockade of Comoros' rebel Anjouan island, using Comorian and Tanzanian soldiers armed with assault rifles and rocket launchers, a senior AU official said. Announced last month, the AU imposed sanctions including a travel ban on some 150 officials on Anjouan, one of Comoros' three main islands, because of disputed polls in June that kept local president Mohamed Bacar in power. "Nothing, no goods can leave or enter Anjouan without being checked by the AU's Electoral and Security Assistance Mission which is patrolling the waters," Francesco Madeira, the AU's special envoy to Comoros, told Reuters over the weekend. The naval operation by the Electoral and Security Assistance Mission (MAES) to Comoros began at 1100 local time (0800 GMT) on Saturday, he said. MAES's boat is equipped with two deck-mounted machine guns and accompanied by two fast patrol boats. It is also carrying roughly 200 Tanzanian and Comorian soldiers armed with assault rifles and rocket launchers, he said. There has been no comment from Bacar on the blockade. The three Comoros islands, which lie off east Africa, retain some autonomy through local leaderships under a 2001 peace deal, but Anjouan's refusal to hold democratic elections had angered national President Ahmed Abdallah Mohamed Sambi. From Anjouan himself and widely supported by the international community, Sambi says he wants to move the Comoros away from a history of political instability that includes 19 coups or coup attempts since independence in 1975.