Soldiers in Madagascar have threatened to seize state TV, President Andry Rajoelina's office has said.
This has delayed his plan to address the nation, it says.
Madagascar's embattled President Rajoelina was supposed to address the nation at 20:30 local time (17:30 GMT), after already postponing his speech once.
Rajoelina's speech had been postponed to 20:30 local time (17:30 GMT) because a group of armed soldiers is threatening to take over the state media headquarters, the president's office has said.
The army's new chief of staff, Gen Demosthene Pikulas, is attempting to resolve the situation, the statement added.
However, a broadcast of his speech has not yet appeared on the state TV channel or his social media platforms.
State TV is currently airing a soap.
Andry Rajoelina, 51, has been fighting for his political survival.
Protesters in Madagascar are waiting for Rajoelina to speak, with one student telling the AFP news agency that he hopes the president "will apologise and genuinely announce his resignation".
"Afterwards, we can consider organising elections and determine who will be suitable to take the leadership role," Finaritra Manitra Andrianamelasoa, 24, added.
Steven Rasolonjanahary,19, said: "We already expect him to offer his apologies to all Malagasy citizens, as we have had many casualties, relatives, who have been injured during the protests."
UN human rights chief Volker Türk previously said at least 22 people were killed and 100 others injured.
Rajoelina disputed the figure, putting the death toll at 12 and "all of these individuals were looters and vandals".
Madagascar's presidency has not given details of the soldiers whom it says have threatened to seize the headquarters of state TV.
Its statement merely said that the army's new chief of staff, Gen Demosthene Pikulas, is at the site, trying to resolve the crisis.
Nor did the presidency answer the question everyone has been asking all day: Where is the president?
There have been numerous reports that Rajoelina has left the country, but there is still no official confirmation - or denial - of this.
Soldiers and security forces in Madagascar's capital joined protesters celebrating Rajoelina's weakened grip on power, AFP reported.
According to the news agency, soldiers from army unit CAPSAT were seen among the crowds on Monday, and so were officers from the gendarmerie, who were previously accused of using heavy-handed tactics to end the protests.
Madagascar is now effectively being run by the powerful military unit known as CAPSAT, a senior leader in Madagascar’s largest opposition party has told me.
The politician pointed to the recent selection of a new army chief of staff, saying that CAPSAT made the appointment and "didn’t consult the appointed ministers".
"It shows they don’t respect them," said the opposition politician, who spoke on condition of anonymity.
