Gambari said at the launch of a book in Lagos on Friday that countries in the continent have continuously remained with the lowest Human Development Index (HDI), noting that "the situation is disheartening".

The book titled "The Curse of Berlin: Africa after the Cold War," was launched at the Nigerian Institute of International Affairs (NIIA).

" Over two thirds of African population of 800 million live below poverty line and the per capita income of most African countries are well below the average.

"Therefore, addressing poverty in Africa should become the major goal of all African governments,'' he said.

Gambari also urged African leaders to tackle insecurity in their countries because there could be no sustainable development without peace.

The UN special representative noted that ensuring good governance and leadership was a major challenge facing the continent.

"Lack of accountability and lack of respect for the rule of law on the part of many leaders, will continue to be major obstacles to the development of African countries.

"It is incumbent on us, to ensure that leaders uphold the rule of law and create a conducive environment for every citizen to achieve his or her potential,'' he said.

Gambari said that the importance of intra-Africa cooperation for the continent's economic development could not be over-emphasised.

The UN official said recent development in Europe and North America has made it imperative for Africans to take concerted measures, aimed at improving intra-African economic cooperation.

"There is no limit to the areas and extent of cooperation among African states, as well as between Africans on the continent and people of African descent in the Diaspora,' he said

Gambari said the book ,written by Dr Adekeye Adebajo, focused on African's quest for security, examined peacekeeping travails and lack of political consensus among African.