President Marc Ravalomanana of Madagascar has defied an ultimatum to resign in the face of a mass opposition rally in the capital, Antananarivo.
After the deadline passed, he emerged from the presidential palace, which is defended by hundreds of his supporters, to say he had no plans to resign.
Opposition leader Andry Rajoelina has threatened to lead a march on the palace if he does not leave.
At least 100 people have been killed since protests broke out in January.
The opposition, which is trying to set up its own government, has occupied the prime minister's offices.
An aide to Mr Rajoelina, who did not wish to be named, said after the deadline passed that the opposition was still waiting for the president to quit.
"If we don't receive the call [from the president to say he has resigned], something will happen," the aide told Reuters news agency.
The BBC's Jonah Fisher reports that the opposition do not seem to have the appetite for a violent confrontation with the president and his supporters and prefer, instead, to keep turning up the pressure.
Nor, our correspondent adds, has there been any indication that the opposition will settle for a coalition with Mr Ravalomanana.
Sticks and stones
Presidential supporters are manning barricades around the park where the presidential palace stands, some 12km (eight miles) from Antananarivo.
Several big orange skips full of sand have been set up about 300m (yds) from the palace and hundreds of people have been walking around, holding large sticks, our correspondent reports.
Some people have got stones and the atmosphere is tense.
Everyone is waiting to see if the opposition do come to try and take the palace but this show of force seems to have called the opposition's bluff and there has been no sign of them moving in on the palace, our correspondent says.
"I'm still the president of Madagascar and I will remain the president," Mr Ravalomanana told the BBC.
"We must have a national conference and respect democracy."
Mr Ravalomanana, democratically elected to a second term in office in 2006, also issued a statement condemning the opposition which, he said, did not have "the power bestowed by democratic elections".
"This [opposition] movement is and remains a street protest which uses terror and repression to survive," he said.
"A self-proclamation does not equate to legitimate power."
Mr Rajoelina, a former mayor of the capital who was sacked by the government last month, rallied some 5,000 supporters clad in orange T-shirts and hats in central Antananarivo on Saturday.
"There is only one demand, that's the departure of Ravalomanana," he said.
But he ruled out using force against the president.
"I have clean hands," said the opposition leader, who accuses the president of being a tyrant who misspends public money.
"I have no intention of killing him [Mr Ravalomanana]. I have no intention of sending in tanks and soldiers."
Mr Rajoelina has been trying to establish an alternative cabinet with himself as president.
On Wednesday, the leader of a widening mutiny within the army ousted the chief of staff and a day later the military police said they would no longer take orders from the government.
The crisis has hurt the country's economy. Its tourist industry, worth nearly $400m (£290m) a year, has now had two months with no revenue.
Under President Ravalomanana, Madagascar's economy opened to foreign investment but 70% of the nation's 20 million population still live on incomes of less than $2 (£1.40) a day.