The pre-dawn attack, one of the deadliest to hit Burkinabe defence and security forces since jihadist violence erupted six years ago, targeted a "detachment of the Inata gendarmerie", the army chief of staff said in a statement.

The attack left 20 dead including a civilian according to a "provisional" toll, Security Minister Maxime Kone said on national radio.

He said the gendarmes "resisted and fought bravely", adding that survivors had been located, with a search still under way for others.

A security source said the assailants drove pickup trucks and motorbikes and engaged in "lengthy exchanges of gunfire" with the gendarmes.

A separate attack occurred Sunday morning in the town of Kelbo, also in Soum province, according to government spokesman Ousseni Tamboura.

"Fortunately, this attack was repelled by soldiers," he said, adding that they were backed by volunteer civilian fighters and there were no casualties.

On Friday, seven police officers were killed and five were wounded in an attack in Alkoma, in neighbouring Seno province, according to police.

The poor Sahel state has been hit by jihadist attacks since 2015, mostly in the northern and eastern regions close to Mali and Niger -- countries facing their own struggles against jihadists -- but also in the south.

Jihadist attacks, often coupled with ambushes and attributed to movements affiliated to the Islamic State group and Al-Qaeda, have killed more than 2,000 people and forced more than 1.4 million to flee their homes.

Last week the political opposition in the former French colony called for urgent steps to deal with what it called a worsening security situation following a surge in jihadist attacks.

They threatened to take to the streets to demand the immediate resignation of President Roch Marc Christian Kabore.