A presidential candidate and a former defence minister have been shot dead by soldiers in Guinea-Bissau who accused them of plotting a coup. Baciro Dabo, a minister and a contender in the election due to be held this month, was killed at his home. The authorities say he resisted arrest but allies insist he was asleep with his wife when he was shot. Former Defence Minister Helder Proenca and two of his guards were also killed in the unstable West African country. There is concern for the safety of former Prime Minister Faustino Fudut Imbali after reports of his death too. Latest reports suggest that Mr Imbali, whose wife says he was taken away by the military, is being detained on suspicion of involvement in the alleged coup plot. An unnamed military source told AFP news agency on Saturday that the former prime minister had been badly beaten up by the soldiers who arrested him, and was now in military police custody. EU foreign policy chief Javier Solana condemned the killings in the former Portuguese colony, and called for a thorough investigation. The 28 June election was called after President Joao Bernardo Vieira was killed by soldiers in March. The BBC's Will Ross says the election may now be postponed. The army looks set to continue to play a destabilising role in a country which has been plagued by coups since independence in 1975, the BBC's correspondent adds. 'Tragic events' Mr Proenca was accused of being the mastermind of the alleged coup. He was killed separately from Mr Dabo. A government statement confirmed their deaths but made no mention of Mr Imbali's fate. "The council of ministers regrets the tragic events that ended in the death of two political figures from whom much more was expected," it said. Earlier, state intelligence services said several other politicians - all members of the ruling PAIGC party -had been detained. "This was about nipping a coup attempt in the bud," they said. "Among the authors of this coup some came quietly while others tried to resist - that is why they were killed. "We have material proof that this coup attempt was aimed at physically eliminating the head of the armed forces, overthrowing the interim head of state and dissolving the national assembly." Journalist Jean Gomis told the BBC's Network Africa programme that Mr Dabo, the minister of territorial administration, had been a close ally of former President Vieira. He said that high-ranking members of the military might have feared that Mr Dabo could prosecute those responsible for killing the president if he won the election. Mr Dabo, 50, was a senior member of the PAIGC but was contesting the election as an independent. He was one of 13 presidential candidates. Mr Vieira was hacked to death with machetes on 2 March by soldiers who blamed him for a bomb which had killed the army chief of staff hours earlier. No-one has been prosecuted over the killing. Source: BBC