International protests are increasing over the coup by army rebels in the West African island state of Sao Tome and Principe.
One of the coup leaders, Sabino Santos, used to be a mercenary in South Africa
Neighbouring African countries, the United States and the United Nations have all condemned the day-old coup.
Soldiers seized key sites and government ministers in a dawn attack on the capital while President Fradique de Menezes was in neighbouring Nigeria.
Coup leader Major Fernando Pereira has told Portuguese radio that he will hold early elections and did not want to remain in power.
The president called for international help to end the bloodless coup.
"Africa cannot attain greatness with bad governance, corruption and coups d'etat," he said from the Nigerian capital Abuja.
Nigeria, which shares sovereignty of potentially oil-rich offshore areas, is sending an envoy to meet with the rebel soldiers.
Nigerian President Olusegun Obasanjo called on the coup leaders to return power to the government.
"We strongly condemn this action and call on the military adventurists to hand over power," he said.
Mr Obasanjo spoke on the phone with the coup leader Major Fernando Pereira, according to the AFP news agency.
It said Major Pereira accepted Mr Obasanjo's proposal for a meeting with the envoy and agreed to reopen the airport Thursday so his plane could land.
Mozambique's President Joaquim Chissano has flown to Nigeria for talks with President Obasanjo on possible military intervention to restore the ousted government, according to Reuters news agency, quoting a senior aide to Mr Chissano.
Mr Joaquim Chissano, who is also chairman of the
53-member African Union, said Sao Tome's neighbours wanted a quick return to order.
"This event constitutes a setback to the efforts of the African Union aimed at restoration of peace, stability
and economic recovery on the whole continent," he told
UN secretary general Kofi Annan joined the condemnation of the coup.
A spokesman said he: "strongly condemns the coup d'etat in Sao Tome and Principe and calls for the immediate and unconditional restoration of constitutional order."
Sao Tome has one of the world's highest foreign debts
The auctioning of oil permits in 2004 is due to net $100 million
Sao Tome will receive 40% and Nigeria 60% of eventual oil revenue
The 160,000 population on the islands faced a dawn-to-dusk curfew which was imposed by troops.
The rebels said they acted to end poverty, although analysts say it is no coincidence that the country is expecting a financial windfall from offshore oilfields.
The coup took place at around 0300 GMT on Wednesday when gunshots, exploding rockets and grenades were heard in the capital, Sao Tome.
The rebels took control of government buildings, state TV and radio, the central bank and the airport.
They also seized key members of the government including Prime Minister Maria das Neves and Natural Resources Minister Rafael Branco, who handles the oil portfolio.
The prime minister was apparently hospitalised after suffering a mild heart attack during a gunfight at her home, according to sources quoted by French news agency AFP.
But Major Pereira said all the detained received medical care and were being well looked after.
Sao Tome is one of the world's poorest countries, and the average annual income of its 160,000 population is a mere $280.
But the country has recently been shaken by a political wrangle, sparked in part by potentially billions of barrels of crude oil lying off its coast.