A mutinying army unit declared on Sunday that it was taking control of all Madagascar military forces as President Andry Rajoelina said an "attempt to seize power illegally" was under way.

The CAPSAT contingent of administrative and technical officers joined thousands of protesters in the city centre on Saturday in a major shift in a more than two-week anti-government protest movement.

The unit had earlier declared that it would "refuse orders to shoot" and criticised the gendarmerie, who have been accused of using heavy-handed tactics against protesters, causing several deaths.

But Sunday the CAPSAT officers claimed in a video statement that "from now on, all orders of the Malagasy army – whether land, air or the navy – will originate from CAPSAT headquarters."

The officers said they had named General Demosthene Pikulas as the head of the army – a post that had been vacant since the former head was appointed minister of armed forces last week – although it was not clear if the posting could be considered official.

Soldiers join protesters in the streets

There was no immediate response from other units or the existing military command.

Soldiers from the unit clashed with gendarmes outside a barracks on Saturday and rode into the city on army vehicles to join the demonstrators, who welcomed them with jubilation and calls for Rajoelina to resign.

Another gathering and a prayer service took place again in the capital on Sunday.

The president released a statement on Sunday saying "an attempt to seize power illegally and by force, contrary to the constitution and to democratic principles, is currently under way."

'Faults'

"Dialogue is the only way forward and the only solution to the crisis currently facing the country," he said, calling for "unity."

Earlier on Sunday, officers of the gendarmerie said in a video statement that they recognised "faults and excesses during our interventions," calling for "fraternity" between the army and the gendarmes.

"We are here to protect, not to terrorise," they said, adding that "from now on, all orders will come solely" from the gendarmerie's headquarters.

Saturday's demonstration in the capital Antananarivo was one of the biggest since the protest movement erupted on September 25, sparked by anger over power and water shortages.

Government says it is 'ready to collaborate and listen'

On Saturday night, the government assured that Rajoelina remained "in the country" and was managing national affairs, while the newly appointed prime minister said the government was "standing strong" and "ready to collaborate and listen."

The CAPSAT contingent is based in the Soanierana district on the outskirts of Antananarivo.

That same military base in 2009 led a mutiny during a popular uprising that brought Rajoelina to power.

The African Union Commission on Sunday expressed "deep concern" at the situation in Madagascar.

AU urges 'calm and restraint'

"The Chairperson of the Commission welcomes the Government’s renewed commitment to dialogue and urges all Malagasy stakeholders, both civilian and military, to exercise calm and restraint," it said in a statement.

Neighbour South Africa also called upon "all parties to respect the democratic process and constitutional order".

The United Nations has said that at least 22 people were killed in the first days of the protests that started on September 25.

Rajoelina has disputed the toll, saying last week there were "12 confirmed deaths and all of these individuals were looters and vandals."

According to local media, the emergency services reported another two dead and 26 injured on Saturday. The CAPSAT unit said a soldier was also shot by gendarmes and died.