Authorities in Burkina Faso say eight soldiers, including a high-ranking commander, have been detained in connection with an alleged plot to “destabilise” the country’s institutions.

The announcement on Tuesday came after President Roch Marc Christian Kabore replaced the entire government amid an escalating security crisis that has led to street protests calling for him to step down.

The military prosecutor’s office said in a statement it had learned of the alleged plot on Saturday after “a member of the gang” denounced the plan.

An investigation has been launched and eight soldiers have been detained for questioning, it added.

Burkina Faso’s government has come under sustained pressure over failures to stem the bloodshed of a brutal six-year conflict with armed groups linked to ISIL (ISIS) and al-Qaeda which has killed some 2,000 people, forced 1.4 million from their homes and spawned an immense humanitarian crisis.

Security sources told the AFP news agency that Lieutenant Colonel Emmanuel Zoungrana, commander of western forces fighting armed groups in the country, was among those arrested.

One of the security sources said “suspicions of a plot to destabilise [the government] with ramifications abroad” had hung over Zoungrana and several soldiers since protests erupted in November calling for Kabore to go over the rising violence.

At the time, the government suspended mobile internet service for more than a week, while the tense situation prompted the United Nations’ special envoy to West Africa to warn against any military takeover.

Governments in parts of the region are on high alert for coups after successful putsches over the past 18 months in Mali and Guinea. The military also took over in Chad last year after President Idriss Deby died on the battlefield.

Neighbouring governments have imposed heavy sanctions on the military rulers in Guinea and Mali in an effort to head off any contagion effect.

In Burkina Faso, Lassina Zerbo, a former UN official who was installed as the prime minister of the new government, has called for “cohesion” in the face of the armed threat.