Portugal has sent a team of investigators and police experts to the tiny equatorial nation of São Tomé and Príncipe, after an "urgent request for assistance" in the aftermath of an alleged attempted coup that left four people dead, authorities in the two countries said.
The team was sent on Sunday, and will "work directly with the judicial authorities" to investigate the events which took place last Thursday night and Friday.
Four people were arrested and later died according to the army chief of staff, who did not give more details on the circumstances, which remain unclear.
The government of São Tomé and Príncipe -- a former colony of Portugal which has been independent since 1975 -- said it "strongly condemned" what it described as a "violent attempt to subvert the constitutional order", while assuring that "all investigations will be carried out to determine the causes and circumstances of the deaths", in addition to the investigations to determine the responsibilities of the attempted coup.
On Tuesday, the European Union "strongly condemned" the attempted coup and called on all political actors to maintain peace in the country.
"We are confident that the authorities will investigate the facts and hold those responsible to account, in accordance with human rights and the democratic values and standards shared by the EU and Sao Tome and Principe," said a spokesperson for EU foreign policy chief, Josep Borrell.
"The European Union is continuing to monitor the situation closely," they added.
What do we know about this alleged coup attempt?
Prime Minister Patrice Trovoada announced on Friday that security forces had killed four people and detained two others including politician Delfim Neves following a thwarted coup attempt.
Trovoada said authorities believe the men were in search of weapons when they entered military barracks and abducted one hostage, who was later freed.
Authorities were investigating whether the men received any support from within the military, he added.
"It's not a robbery, it's not a theft," Trovoada said. "It's an attack with weapons of war on the country's armed forces and we have to solve this problem."
The attack comes about two months after São Tomé and Príncipe held parliamentary elections, which were won by Trovoada's Independent Democratic Action (ADI) party.
He was sworn in as prime minister earlier this month.
Neves, of the Democratic Convergence Party, has run for president twice and had contested the results of last year's race.
The archipelago of São Tomé and Príncipe is located near the equator about 350 kilometres off the western coast of Africa near Gabon.
About 225,000 people live in the former Portuguese colony, which has seen several coup attempts, including in 2003 and 2009. But since then the island nation has been considered a model of parliamentary democracy in Africa.
The government has alternated several times between the two main parties: the centre-left Movement for the Liberation of São Tomé and Príncipe-Social Democratic Party; and Trovoada's centre-right Independent Democratic Action (ADI).