OCT. 31, 2014/The New York Times

Reuters reported that a heavily armed convoy carrying the president was seen leaving the capital and heading south toward Po, near the border with Ghana, even as his resignation announcement was being read out on television. It was not clear who would replace him.

The announcement came on the fourth day of turmoil in Ouagadougou, the capital, which culminated in a closed-door gathering of military commanders.

Earlier on Friday, huge crowds gathered in Ouagadougou, where senior army officers met to decide their next step. One officer, who was not identified by name, told protesters that the “army is henceforth at the side of the people.”

News agencies quoted an announcement from the president as saying he had stepped down in face of the protests and calling for elections within 90 days.

Overnight, the president said he had “heard the message” from the protesters and understood “the strong desire for change.”

In a televised statement late Thursday, Mr. Compaoré rescinded a declaration of martial law, made only hours earlier, and offered negotiations on “a transitional period at the end of which I will hand over power to the democratically elected president.”

He also abandoned plans to change the Constitution in order to run for office again next year — the issue that has ignited days of protest. But he rejected calls for his immediate resignation.

On Friday, protesters in the capital of this impoverished West African nation urged the military to sweep Mr. Compaoré from office. Demonstrators looted at least two banks and ransacked many stores, residents said.

Opposition politicians appealed to their followers to “keep up the pressure by systematically occupying the public space.”

Rejecting Mr. Compaoré’s offer of talks, 34 opposition groups also said the “precondition for any discussion of a political transition is the unconditional departure, pure and simple, of Mr. Blaise Compaoré.”

Opposition to the president’s plans for another term had been building for weeks.

Anger exploded Thursday as protesters stormed the Parliament building, bursting past police lines to prevent lawmakers from voting on a draft law that would have allowed Mr. Compaoré to run again next year.

Thousands rampaged through Ouagadougou, burning the homes of presidential aides and relatives and looting state broadcasting facilities. Social media sites showed images of demonstrators toppling a statue of Mr. Compaoré.

The violence set off a series of decrees from the embattled president, who declared martial law, permitting the military to suspend both the Parliament and the government, and to inaugurate a 12-month transition to elections under an interim government.

Opposition leaders called his actions a coup.

In his statement late Thursday, Mr. Compaoré, a former army officer who seized power in a coup in 1987 and ranks among Africa’s longest-serving leaders, said that the government would remain “dissolved,” but that martial law would be “canceled.”