Donkeys have been banned from entering Kenya's north-eastern town of Wajir unless they wear nappies.

Officials say the rule is to protect the town's newly laid tarmac road.

A letter told donkey-cart owners they must manage their animal's faeces "to avoid poop all over the tarmac road creating nuisance".

BBC Monitoring's Abdullahi Yusuf Osman in Kenya says cart owners are complying - some sharing tips on social media on how to attach nappy sacks.

Donkey carts are a common sight in Wajir's town centre, our reporter says.

A similar nappy order was issued in Limuru, about 50km north-west of the capital, Nairobi, in 2007 but it was never put into practice, he says.

The authorities in Wajir, which is more than 600km north-east of Nairobi, are probably keen to protect the new tarmac road after waiting decades for such development, our correspondent says.

The new road was built last year and is 27km long.

The nappy notice was issued on Monday and came into affect on Thursday.

"[The county government] appreciates the contribution of the donkey-cart operators to the economy of Wajir... However the town must be kept clean at all times," it says.

"In view of the above you are directed to manage your donkey poop (faeces).... No donkey will be allowed in town without this poop-collecting bag."