After a series of fruitless negotiations and proposals, sanctions against Anjouan's "illegal authorities" are the African Union's (AU) latest attempt to resolve the political deadlock between the Union of Comoros and one of its semi-autonomous islands.

The AU has been trying to negotiate a resolution to the conflict since individual island elections in June reignited inter-island hostility between Anjouan and the other two islands in the archipelago, Grande Comore and Moheli. The Indian Ocean island group has a population of around 800,000.

The archipelago's complex electoral system was brokered in 2001 by the Organisation of African Unity (OAU), the AU's predecessor, in the wake of Moheli and Anjouan seceding from Grand Comore in 1997. The electoral system provides for a semi-autonomous government and president for each island, with a rotating presidency for the overarching Comoros Union government.

"Further delay in the resolution of the crisis would further destabilise the Comoros and seriously jeopardise the unity of the country," said an AU statement released after its Peace and Security Council adopted sanctions against Anjouan's leadership at a meeting on Wednesday.

"All [AU] member states shall immediately freeze the funds, other financial assets and economic resources owned or controlled by the illegal authorities of Anjouan," while other sanctions included restricted travel. According to the statement, a comprehensive list of affected individuals is to be circulated.

Mohamed Bacar, 45, who first came to power in a 2001 coup and was elected president of Anjouan in 2002, was asked to step down by the constitutional court on grounds that he had served his five-year term, and nominated an interim president to head the island's government until the elections were held.

The first round of elections were held on 10 June on Grande Comore and Moheli but the AU and the Union government postponed the poll on Anjouan until 17 June, after intimidation in the run-up to voting and incidents of violence claimed the lives of two soldiers.

"The election on Anjouan [held on 10 June despite the postponement] were declared null and void by the African Union and the Comoros constitutional court," Francisco Madeira, the AU special envoy, told IRIN. Bacar claimed a landslide victory of 90 percent.

The AU sanctions apply for an initial period of 45 days, and will be lifted if the Anjouan authorities agree to hold new elections. Bacar has dismissed calls for new elections, endorsed by the Union government.

In the event of Bacar's continued non-compliance with the AU and Union government demands, stronger measures would be implemented, such as an air and sea blockade of the island, "as well as MAES [the AU Electoral and Security Mission to the Comoros] support to the Comorian government to enable it to take all measures necessary to restore its authority on Anjouan," the statement said.

Comoros gained independence from France in 1975 after more than a 130 years of colonial rule, but has experienced 19 successful and attempted coups in three decades of political instability.