Authorities in Guinea-Bissau said yesterday they foiled an attempted coup, and security forces killed two people allegedly involved, including a candidate in the West African nation's upcoming presidential ballot.

A statement issued by Guinea-Bissau's intelligence service said the coup plot was masterminded by former defence minister Helder Proenca. It said presidential candidate Baciro Dabo was also involved. Portugal's national news agency Lusa reported.

Both men were confirmed dead in separate shootings.

"This being a subversive act and its perpetrators being armed, police help was requested in order to disarm them,” the intelligence service statement said. "During the operation some gave themselves up while others resisted, bringing an exchange ofgunfire that caused their deaths."

There were'no details of how many people were involved in the plot, or whether any are under arrest.

A former Portuguese colony, Guinea-Bissau has a tong history of instability with numerous coups and attempted coups, most of which were led by the army.

The West African country's president, Joao Bernardo "Nino" Vieira, was assassinated March 2, just hours after his longtime rival, the head of the armed forces, was killed by a bomb.

An interim government was set up after Vieira's death and elections to choose a new leader are due June 28, with campaigning to begin Saturday.

The intelligence service statement alleged that former Prime Minister Faustino Imbali and retired armed forces officers were also involved in the attempted overthrow. The plotters planned to oust the interim president, dissolve parliament, and kill armed forces Chief of Staff Zamora Induta and Prime Minister Carlos Gomes Junior, the statement said.

The statement claimed intelligence officials had audio recordings and filmsof the plotters preparing the coup.