While en route back to Kampala on Monday morning, Otunnu's vehicle was run off the road by vehicles belonging to Museveni's Presidential Guard Brigade (PGB). "It was really a miracle no one was hurt," Otunnu told AFP. "We were coming from behind, and they clearly made way for us to pass.

Then, the third vehicle in the convoy came out into the middle of the road, where we were passing."

Museveni was not travelling in the five-car convoy and had left Gulu by helicopter on Sunday.

Otunnu explained that his driver was forced into a series of precarious manoeuvres, which ended when his vehicle slammed into a group of mango trees on the opposite side of the road.

At that point, Otunnu said, PGB soldiers surrounded him and his entourage, with guns trained. "They were calling out my name," he told AFP. "They seem to have known who I was, even though I had not yet left the vehicle."

He said the soldiers refused to identify themselves, removed the number plates from their vehicles and removed the name tags from their uniforms as Otunnu and staff approached.

He said the PGB soldiers confiscated the video camera of a Ugandan journalist travelling with him. Otunnu is seen as a strong contender in the 2011 presidential race while Museveni, in power since 1986, has not ruled out seeking re-election.