Gunmen have attacked and wounded Uganda's Transport Minister and former army commander, Gen Katumba Wamala, killing his daughter and driver.

Witnesses say men on motorbikes fired several shots at their vehicle near their home in the capital, Kampala.

Uganda's president has said "we already have clues to those killers" calling them "pigs" and "terrorists".

Soldiers are guarding the hospital where Gen Wamala is being treated for non life-threatening injuries.

He is regarded as one of Uganda's most respected politicians and military men.

The attempt on his life comes as a shock although such attacks are not rare, the BBC's Patience Atuhaire reports from Kampala.

It is not clear what the motive for the attempted killing was. The army says phone calls potentially linked to planning the assassination attempt are being investigated.

Gen Wamala was previously a police chief as well as formerly heading the army.

At the time of Tuesday's attack, he was travelling in an army vehicle that was sprayed with bullets from the sides and front.

According to a police statement, four armed men on "motorbikes with concealed number plates" had followed the car for 4km (2.5 miles) down the road from Gen Wamala's home before opening fire.

His 26-year-old daughter Brenda Nantogo and his driver, Haruna Kayondo, were "killed instantly" say police. The general's bodyguard - Khalid Koboyoit - is said to have survived with no injuries.

Video footage from the scene in Kiasasi, a suburb of Kampala, shows the former army chief visibly shaken and covered in blood - being rushed to hospital on the back of a motorbike.

Over the last few years, the country has been rocked by shootings by armed men riding on motorcycles, our correspondent says.

In June 2018, Ibrahim Abiriga, a politician and ardent supporter of President Museveni, was shot and killed near his home.

Former police spokesperson Andrew Felix Kaweesi was killed in a similar manner in April 2017 as were a magistrate and several Muslim clerics.

None of these killings has ever been successfully investigated or prosecuted.

Yet in a series of tweets on Tuesday, President Yoweri Museveni vowed to "defeat the criminals as we did in the past".