Guinea-Bissau's junta and its political backers faced further sanctions Friday as the international community condemned the establishment of an "illegal" two-year transition government.

Portugal's Foreign Minister Paulo Portas called for a visa ban and asset freeze on military leaders and opposition who struck a deal with them to dissolve government after an April 12 coup.

Addressing the Security Council, he indicated the European Union was about to order the measures, while supporting a call by Guinea-Bissau's foreign minister and Angola for a peacekeeping force in the chronically unstable nation.

Pressing forward with their transition plans opposition parties and the junta on Thursday named former parliamentary speaker and independent presidential candidate Manuel Serifo Nhamadjo to lead the interim government.

The ruling party, whose presidential candidate and former prime minister Carlos Gomes was leading an election process aborted by the coup, has been excluded from the deal.

The Economic Community of West African States (ECOWAS) has called an emergency summit on the situation next week over what it calls an "illegal initiative."

"The ECOWAS Commission has learnt with surprise the announced establishment of a so-called 'Transitional National Council' by the Military Command Junta and 24 political parties in Guinea Bissau to govern the country for a two-year period," the statement said.

"The commission strongly condemns this illegal initiative, particularly after the junta had given a written undertaking, following its meeting with a high-level ECOWAS delegation in Bissau on 16 April 2012, to step aside to pave the way for the immediate return to constitutional normality with the facilitation of ECOWAS."

A high-ranking west African delegation made up of ministers and chiefs of staff had visited Bissau on Monday to meet the coup leaders.

"The commission wishes to reiterate its rejection of the usurpation of power by the military command, and to make it known that it will never recognise any transitional arrangement emanating from the junta," the statement said.

The former ruling African Party for the Independence of Guinea and Cape Verde (PAIGC) and smaller allied parties denounced the "irresponsible, undemocratic attitude of certain politicians hiding behind the military to access power."

The World Bank and the African Development Bank have frozen development programmes to the country which has already been suspended from the African Union.

The international community has also called for the release of interim president Raimundo Pereira and Gomes, along with other top officials arrested during the coup.

Since 1998, Guinea-Bissau has been through one war, four military coups and the murder of one president and four military chiefs of staff. No president has ever completed a full term in office.

This has allowed cocaine trafficking to Europe to flourish, leading the former colonial power Portugal to warn that the country faces a stark choice.

"What is at stake is a choice between a state based on constitutional rule or a failed state based on the power of drug trafficking," Portas said.

"The responsibility for these acts belongs to certain elements of the armed forces and a few politicians who keep fuelling instability and institutional weakness of the country."

Mamadu Saliu Djalo, the Guinea-Bissau foreign minister who was away at the time of the coup and has been unable to return, told the Security Council, "I beg for action."

He called for the deployment of an intervention force and was backed by Portugal and the main group of Portuguese-speaking nations.

The Portuguese-speaking group and the West African regional group are already discussing a possible force, diplomats said.

Two weeks before a run-off election on April 29 soldiers ousted government over its growing reliance on a large contingent of Angolan troops stationed in the country.

With coups and army assassinations an ever-present threat, observers say Gomes was seen as setting up a private security force after he was abducted during an army mutiny in April 2010.