Uganda's Deputy Prime Minister Moses Ali has told parliament that the opposition MP and musician Robert Kyagulanyi, popularly known as Bobi Wine, has been flown to a military hospital in Gulu - in the north of Uganda - for medical treatment.

He was detained along with three other MPs and dozens of his supporters ahead of Wednesday's controversial by-election in Arua, a north-western town bordering the Democratic Republic of Congo and South Sudan.

He is due to appear in court in Gulu on Thursday, Mr Ali said.

The arrests in Arua followed an attack on President Yoweri Museveni's convoy on Monday. Wine's driver was later shot dead. (See earlier post)

The by-election is taking place because the previous MP was shot dead.