President Kumba Yala of Guinea-Bissau swore in a new Prime Minister on Sunday after dissolving parliament and calling early elections, news organisations reported.
Mario Pires, 53, took office as caretaker Prime Minister replacing Alamara Nhasse. An announcement of new ministerial appointments was expected on Monday, the Portuguese news agency, Lusa reported.
Security was beefed up and police sealed all government ministries in the capital, Bissau, over the weekend and said they had orders only to allow sacked ministers and state secretaries to enter and leave - "empty handed", Lusa added.
It quoted Pires as telling reporters his mandate was "to serve the people under the orientation" of the president.
Yala announced on Friday that the early elections would take place within 90 days. He accused the legislature of "subversion" and charged his minority Social Renovation Party government with corruption.
Yala came to power in January 2000, since then, the country has been wracked by crises, including a rebellion by members of the former military junta in November 2000, a coup attempt in December 2001, and the dismissal of several ministers in recent months. Opposition parties recently demanded Yala's resignation, blaming him for the country's economic crisis and political instability.