The military has often got involved in politics

They include the former president of the supreme court, Emilano Novolini dos Reis and his vice president who were sacked in September by Mr Yala who described them as corrupt, mediocre, liars and false.

Government officials say they are investigating the disappearance of around $100,000 from the account of the Supreme Court but Mr dos Reis denies any wrongdoing and says the money has already been accounted for.

Human rights group Amnesty International has called the arrests of the judges a serious attack on the independence of the judiciary, with the United Nations secretary general Kofi Annan describing the political situation in Guinea Bissau as dangerously unstable.

'Absolutely illegal'

Also detained are senior two journalists from a private newspaper. Their detention comes at a time of mounting criticism from both inside and outside the country over what opponents see as the president's erratic behaviour.

Ligio Monteiro of the BBC's Portuguese Service says the arrests of the judges is " absolutely illegal" and against the constitution of the country.

He said the by law the court's accounts should have been audited by an independent commission and this was not done.

Lawyers have gone on strike in protest at the sackings and parliament has also criticised the president.

Mr Yala hit back, warning earlier this month that he could suspend parliament for 10 years if he so chose.

Media trouble

He said that his priority was to fight corruption and rescue Guinea Bissau from poverty.

Mr Yala's relationship with the press has also being strained.

Vieira was overthrown by the army two years ago

Diario de Bissau, the daily newspaper whose senior staff are under arrest, was banned in late October after the authorities accused the paper of inciting hatred and tribalism.

Guinea Bissau suffered a series of bloody military coups following its independence from Portugal in 1974.

Mr Yala was elected president in February 2000 after Joao Vieira was overthrown by the army.

He has already faced a military revolt and there have been warnings of possible unrest from hostile sections of the army.