Emergency summit in Guinea-Bissau

President Vieira was apparently killed in a revenge attack

Regional leaders are visiting the West African state of Guinea-Bissau in an effort to defuse the crisis following the assassination of the president.

Soldiers shot dead Joao Bernardo Vieira on Monday in an apparent tit-for-tat attack after army chief-of-staff Gen Tagme Na Waie was blown up.

West African regional group Ecowas is due to hold an emergency summit about the crisis in the capital, Bissau.

The city reportedly remains calm in the aftermath of the double assassination.

The African Union's Peace and Security Council convened on Tuesday in the Ethiopian capital Addis Ababa to discuss their response to the crisis.

According to the AU's statutes, member-states should be suspended in the event of an unconstitutional power-change, as were Mauritania and Guinea after coups last year.

The 53-member body has branded the killings "cowardly and heinous attacks".

Ecowas Chairman Mohamed Ibn Chambas has called the double killing "the assassination of democracy".

Gen Tagme Na Waie and the president were bitter enemies

Guinea-Bissau's army has denied it is launching a coup and is promising to respect the constitution.

Under the charter, the speaker of parliament has now taken office and must arrange elections within 60 days.

Mr Vieira, 69, is thought to have been killed by renegade soldiers who blamed him for the death of the army chief on Sunday.

The AU, the European Union and former colonial ruler Portugal have called for a respect for the rule of law.

Guinea-Bissau has been plagued by coups and political unrest since it gained independence from Portugal in 1974.

It has also become a major hub for the trafficking of cocaine from Latin America to Europe.

Army officers have been accused of involvement in drug-smuggling but experts say there is no evidence that the power-struggle was directly linked to the trade.