Kumba Yala, the former president of Guinea-Bissau, staged a symbolic occupation of the presidential palace during the early hours of Wednesday morning to press his demand for immediate reinstatement as head of state.
General Jose Loa, the head of the presidential guard, told reporters that Yala and several accomplices let themselves into the empty single storey building through a back door at 4 a.m., evading the vigilance of a single soldier who was standing guard at the front entrance.
Yala and his companions left the presidency a few hours later after General Tagme na Wai, the chief of staff of the armed forces, issued an ultimatum, broadcast by two local radio stations, demanding that they leave by 8 a.m.
An IRIN correspondent later saw Yala sitting in the lounge-room of his house in a suburb of the capital Bissau. The former president, who was deposed by a bloodless coup in September 2003, was smoking a pipe and looked on edge. He declined to speak to reporters.
His brief occupation of the presidential palace prompted an angry reaction from a group of about 100 youths who marched on Yala's house. Eyewitnesses said one of Yala's private bodyguards shot and wounded one of the demonstrators, who was rushed off to hospital.
The angry youths then headed for the town centre where they set fire to the headquarters of Yala's Social Renovation Party (PRS) and three vehicles outside the building.
The government led by Prime Minister Carlos Gomes Junior held an emergency cabinet meeting to discuss the crisis, which erupted as Guinea-Bissau heads towards presidential elections on 19 June to complete its return to democracy.
Interim President Henrique Rosa, who sleeps in his own house at night, later turned up to work as usual at the presidential palace.
Everyday life in Bissau, a city of 300,000 people, appeared to be little affected by the bizarre turn of events.
People went about their business normally, but the city's only commercial bank, the Banco da Africa Occidental, remained closed as a precautionary measure.
Yala is standing as the official PRS candidate in next month's presidential election.
However, on 15 May, the former philosophy lecturer made a surprise announcement that he was withdrawing his resignation as head of state, forced upon him by the army two years ago. He said he intended to return to power and complete the rest of his five-year elected term.
Yala's declaration gave rise to deep concern at home and abroad.
It prompted the presidents of Nigeria, Niger and Senegal and the prime minister of Guinea-Conakry to visit Guinea-Bissau on Saturday for talks with the country's political and military leaders to ensure that the presidential election would go ahead smoothly.
However, the talks ended abruptly when Nigerian President Olusegun Obasanjo walked out of a meeting with Yala after the deposed leader insisted on describing himself as the present head of state, not simply as a candidate for the presidency.
The brief occupation of the presidential palace on Wednesday morning marked the first time that Yala had actually taken concrete action to assert his claim to the presidency.
He was elected with a large majority in 2000 on a platform of national reconciliation after a civil war,
However, his government rapidly degenerated into administrative and financial chaos. Yala dismissed parliament in November 2002 and failed to hold fresh elections. He sacked half the judges of the Supreme Court and engaged in constant cabinet reshuffles. Meanwhile, his government stopped paying the wages of most public employees.
Yala's removal from power was greeted with widespread relief, but he has since made a comeback, gathering support from his Balanta ethnic group. This comprises a third of Guinea-Bissau's population of 1.3 million and dominates the army.
Yala's PRS lost parliamentary elections in March last year to the African Party for the Independence of Guinea-Bissau and Cape Verde (PAIGC), which currently holds power.
The PAIGC is fielding Malam Bacai Sanha, a relatively low-profile figure, as its official candidate in this year's presidential poll.
But diplomats and local political analysts reckon he will face a tough challenge from Yala and from Joao Bernardo "Nino" Vieira, another equally controversial former head of state.
Vieira is a former army general who seized power in a 1980 coup. He ruled this former Portuguese colony for 19 years, until he was forced to quit during the latter stages of the 1998-1999 civil war. Vieira has lived in exile in Lisbon since then.