(AFP) - The African Union on Monday suspended Burkina Faso a week after the volatile country suffered its latest coup, as diplomats from West Africa and the UN began talks with the new junta.

The AU's 15-member Peace and Security Council said on Twitter it had voted "to suspend the participation of #BurkinaFaso in all AU activities until the effective restoration of constitutional order in the country".

The move came three days after the Economic Community of West African States (ECOWAS) suspended Burkina from its ranks and warned of possible sanctions pending the outcome of meetings with the junta.

An ECOWAS mission headed by Ghanaian Foreign Minister Shirley Ayorkor Botchway arrived in Ouagadougou, where it was joined by the UN's special representative for West Africa and the Sahel (UNOWAS), Mahamat Saleh Annadif.

They arrived at the presidential palace at 1 pm (1300 GMT), an AFP journalist saw.

"The joint delegation will have meetings with the military leaders as well as with the various Burkinabe actors," UNOWAS said in a statement earlier.

On Saturday, ECOWAS sent military chiefs to confer with junta leader Lieutenant-Colonel Paul-Henri Sandaogo Damiba.

The junta "reaffirmed its commitment to sub-regional and international organisations," it said in a statement.

ECOWAS leaders will hold a summit in Accra on Thursday to assess its two missions to see whether they should impose sanctions.

They have previously suspended and enforced sanctions against two other members -- Mali and Guinea -- which have also seen military overthrows in the past 18 months.

Moussa Faki Mahamat, who chairs the AU's Commission, had already condemned the coup on the day it happened.

- Troubled country -

On January 24, rebel soldiers detained president Roch Marc Christian Kabore amid rising public anger at his failure to stem jihadist violence ravaging the impoverished nation.

They later released a handwritten letter in which he announced his resignation -- a document that a member of his party said was authentic.

The junta has dissolved the government and parliament and suspended the constitution, vowing to re-establish "constitutional order" within a "reasonable time".

The coup is the latest bout of turmoil to strike Burkina Faso, a landlocked state that has suffered chronic instability since gaining independence from France in 1960.

Kabore was elected in 2015 following a popular revolt that forced out strongman Blaise Compaore.

Compaore himself had seized power in 1987 during a coup in which the country's revolutionary leader, Thomas Sankara, was gunned down.

He was re-elected in 2020, but the following year faced a wave of anger over his handling of a jihadist insurgency that has swept in from neighbouring Mali.

Since 2015, more than 2,000 people have died, according to an AFP toll, while the country's emergency agency says a 1.5 million people, in a population of 21 million, have fled their homes.

- Sankara trial -

In a separate development on Monday, a military court in Ouagadougou said the long-awaited trial of Sankara's alleged killers was being suspended until "the restoration of the constitution".

Civilian plaintiffs had requested the suspension, arguing that the independence of the court was guaranteed by the constitution, and proceedings therefore could not continue if the constitution had been suspended.

The trial opened last October and has been closely followed by the Burkinabe public.

It has been showcased as the chance to shed light on one of the murkiest chapters in the troubled country's history.

Fourteen defendants are on trial, two of them in absentia, including Compaore.

Compaore and his former right-hand man General Gilbert Diendere are charged with harming state security, complicity in murder, concealing bodies and witness tampering.

Compaore has repeatedly denied entrenched suspicions among Burkinabe that he ordered Sankara's killing, while Diendere has pleaded not guilty.

Diendere is already serving a 20-year term for an attempted coup in 2015.

© Agence France-Presse