The president of Guinea, Lansana Conte, has reportedly sacked Prime Minister Cellou Dalein Diallo in an apparent power struggle between the two men.
Prime Minister Diallo has been accused of "grave misconduct"
The dismissal comes a day after a state radio broadcast announcing greater powers for Mr Diallo was interrupted by soldiers who burst into the studio.
A statement from President Conte, broadcast on Wednesday, said Mr Diallo had been sacked for "grave wrongdoing".
Mr Conte is said to be very ill and has been receiving medical care abroad.
While the septuagenarian president was recently receiving treatment in Switzerland, opposition groups in the Guinean capital, Conakry, called for the formation of an interim government.
Guinea has avoided the wars that have ravaged its west African neighbours but its failing economy, rife corruption and feuding military have raised fears of unrest in the resource-rich country.
Wednesday's presidential statement sacking Mr Diallo also reversed a cabinet reshuffle announced on Tuesday.
State radio said on Tuesday that several cabinet ministers - regarded as loyal to Mr Conte - were being replaced with allies of Mr Diallo.
The radio station added that many ministerial powers were being transferred directly to Mr Diallo.
The broadcast was interrupted by soldiers who stormed the studio.
A top Guinean media official told the Reuters news agency the broadcast was halted because an aide to the president, Fode Bangoura, had not been informed beforehand.