Bram Verelst, a Burundi-based researcher with the Institute for Security Studies (ISS) think-tank, said the assault appeared to be an attempt to force Burundi to withdraw the troops it had in eastern DR Congo backing the army against the rebel forces and Rwanda.

Ukraine and the US are due to hold a second day of talks in Berlin on a plan aimed at ending Russia’s war, with allied security guarantees for Kyiv a central focus of the negotiations.