The aim was to stem the jihadist insurgencies ravaging parts of West Africa.

Burkinabe Defence Minister Maxime Kone said almost 6,000 troops had been deployed in the four countries' borderlands, arresting 300 people and seizing vehicles, weapons, ammunition and drugs.

He said dozens of Islamist militants were killed and that five jihadist bases had been destroyed in his country.

The details can't be independently verified, but this week-long operation arose from a security deal the countries signed in 2017.

More than 70 people have been killed in militant attacks in Burkina Faso in November, prompting a public outcry.

Most other countries in the Sahel region have also suffered losses.