LAGOS, Oct. 19 (Xinhua) -- The Authority of Heads of State and Government of Economic Community of West African States (ECOWAS) has banned President Mamadou Tandja of Niger and his Guinean counterpart Moussa Camara from contesting elections in their countries, the regional bloc said.

The ban was contained in a communique issued at the conclusion of an extra ordinary summit convened by ECOWAS chairman and Nigeria's President Umaru Yar' Adua in the capital Abuja over the weekend.

The communique was read by Mohamed Ibn Chambas, president of the ECOWAS Commission, after a closed-door session of the leaders. It also called for immediate return to constitutionality in both countries.

ECOWAS condemned the referendum held in Niger on Aug. 4 to allow Tandja's participation in the presidential election, denouncing it as a violation of the ECOWAS supplementary protocol on democracy and good governance.

The regional leaders urged Tandja to suspend indefinitely the holding of legislative elections scheduled for Oct. 20 and to go into dialogue with the political parties over the matter.

Liberian President Ellen Johnson-Sirleaf led a three-man delegation which also included Abdulsalami Abubakar and Chambas to deliver the message to Tandja on Oct. 18.

The summit threatened to impose full sanctions on Tandja as stipulated under article 45 of the supplementary protocol on democracy and good governance if he failed to comply with the decisions.

It, however, imposed a minor sanction on the country by refusing to support candidates from Niger seeking elective posts in international organizations.

It also resolved not to organize ECOWAS meetings in the country.

As regards Guinea, the summit called for a new authority to ensure a short and peaceful transition to constitutional order through credible, free and fair elections.

It reiterated its desire that Camara and members of his cabinet should not contest the presidential election billed to take place in January 2010.

The summit mandated Chambas to work with the African Union (AU)on a regime of targeted sanctions against individuals, who would pose a threat to the implementation of the transitional agenda.

An arms embargo was also imposed on Guinea under the ECOWAS Convention on Small Arms and Light Weapons to forestall further killings of innocent people.

Earlier, Yar'Adua lamented the deteriorating political and human rights situation in both countries, calling for a holistic approach to resolve the crises.

The heads of state from Benin, Burkina Faso, Guinea Bissau, Liberia, Nigeria, Sierra Leone and Togo attended the meeting, while the other leaders were represented.