In a highly unusual tactic, militants suspected to be linked to the Islamic State (IS) group used a donkey strapped with explosives to ambush the convoy of the governor of Nigeria’s north-eastern Borno state, an official who was in one of the vehicles has told the BBC.

The latest ambush came after Governor Babagana Zulum survived an attack by militants while he was travelling to an area near Lake Chad on Friday.
His convoy was ambushed again on Sunday as he was returning to the state capital, Maiduguri, and this time militants putting a donkey on the road, the official said.
When soldiers saw it, they shot at the animal. Explosives then went off and the militants immediately came out from their hide-out to open fire on the convoy, the official added.
A number of insurgents were killed in the ensuing shoot-out. No-one in the convoy – including the governor – was injured but some vehicles were damaged by bullets, the official said.
At least 18 people – 14 police officers and soldiers and four civilians – were killed in Friday’s ambush.
The governor had toured Baga town in preparation for the return of thousands of residents displaced by Boko Haram militants in 2014.
Boko Haram has since split, with a breakaway group – the Islamic State West Africa Province – pledging allegiance to IS. (Courtesy BBC)