OUAGADOUGOU (AFP) - The second in command of Burkina Faso's presidential guard, Colonel Isaac Zida, said on Saturday he has assumed power as head of state during the transition period, saying a similar claim by the army chief is "obsolete".

"I now assume... the responsibilities of head of the transition and of head of state to assure the continuation of the state" and a "smooth democratic transition", said Col Zida in a televised speech. He is leading a group of young officers opposing a similar claim to power made by army chief Nabere Honore Traore on Friday.

He also said the deposed president Blaise Compaore, is "in a safe place" and his "safety and well-being are assured". He told journalists that Mr Compaore, who resigned on Friday, and his chief of staff "are in a safe place and their safety and well-being are assured".

Rival army factions were tussling over the future of Burkina Faso on Friday after Mr Compaore reportedly fled the capital. General Traore announced he was assuming power after an extraordinary week of violent protest against Mr Compaore's 27-year rule that saw Parliament stormed and set ablaze. But his bid for control was quickly challenged by a group of young army officers who said they had "taken the destiny of the nation in hand".

Earlier, speaking before large crowds in the Place de la Nation, site of some of the week's fiercest clashes, Col Zida had said a "transitional body" would be established to restore constitutional order.

He appeared alongside lawyer Guy Herve Kam, leader of the Citizen Broom group that helped lead the demonstrations in the poverty-stricken west African nation.

Col Zida also ordered the closing of the country's borders as reports suggested the president had fled.

A French diplomatic source told AFP that Mr Compaore was travelling south towards the town of Po near the border with Ghana.

The source said he was still in the country and had not asked for refuge in France, the former colonial power.

The uprising, which has drawn parallels with the Arab Spring, was sparked by plans to change the constitution to allow Mr Compaore to stand once again for elections next year.

Mr Compaore is one of several sub-Saharan African leaders who have stayed in power for decades, and the protests are being closely watched across the continent where at least four heads of state are pressing for similar constitutional changes to cling to power.

Many protesters are deeply opposed to army chief Traore taking power as he is seen as a close ally of Mr Compaore.

"We do not want General Traore in power. We need someone credible. Traore is Blaise Compaore's henchman," said Mr Monou Tapsoaba, an activist with the opposition People's Movement for Progress.

The army chief announced on Thursday that the government had been dissolved. The army imposed a dusk-to-dawn curfew and pledged to restore constitutional order within 12 months in a statement signed by Traore.

One opposition leader Benewende Sankara described the move as a "coup".

Another opposition chief Zephirin Diabre told AFP he hoped the two military factions will forge an agreement.

"We await the army's plans for the transition. We will tell them what we think," he said.

Many of the tens of thousands massed on the streets of the capital have called for retired general and former defence minister Kouame Lougue to take control, shouting: "Lougue in power!"

France's President Francois Hollande vowed that Paris would "contribute to calming" the situation in its former colony, while Washington urged "a transfer of power in accordance with the Constitution".

The European Union called for the people of Burkina Faso to have the final say in who rules their country.

The crisis is the worst in Burkina Faso since a wave of mutinies shook the country in 2011.

Mr Compaore had initially rejected calls to resign. He withdrew plans for a vote on the constitutional changes but vowed to stay in power for another year.

He was only 36 when he seized power in a 1987 coup in which his former friend Thomas Sankara was ousted and assassinated.

His bid to cling to power angered many, particularly young people in a country where 60 per cent of the population of almost 17 million is under 25.

Many have spent their entire lives under the leadership of one man and are disillusioned by the establishment running the poor former French colony, which is stagnating at 183rd out of 186 countries on the United Nations human development index.

The death toll from Thursday's violence - the peak of the unrest - was given as "around 30" by two opposition leaders.

"Oct 30 is Burkina Faso's 'Black Spring', like the Arab Spring," Mr Emile Pargui Pare, an official from opposition party the Movement of People for Progress, told AFP.

Known in colonial times as Upper Volta, the landlocked country became independent from France in 1960 and its name was changed to Burkina Faso ("the land of upright men") in 1984.