Besigye told supporters the government was failing to respond to popular discontent [Reuters]

Ugandan security forces have arrested Kizza Besigye, the leader of the opposition, for a fourth time in three weeks a day after he was freed on bail.

Besigye, who has previously been detained on trumped-up charges of rape and treason, was arrested in Kampala, the capital, as he resumed his protest against spiralling food and oil price in the east African nation.

The runner-up to veteran President Yoweri Museveni in a disputed February election has been detained by police in the past couple of weeks over the protests that have killed at least five people.

He was freed on Wednesday on bail on condition that he does not stage more protests. He had spent one week in dention in Nakasongola.

Al Jazeera's Malcom Webb in Kampala said: "This morning he set off walking from his house again in contravention of the bail order. As he reached the end of his drive, police instructed him he had to proceed in his car. He agreed but drove into Kampala city centre [and] attracted very large crowds of agitated supporters - seems the whole procees of his arrest and release has only added to his poularity."

Our correspondent added: "There was a two-hour standoff at a roundabout where police wouldn't let him drive the way he wanted to drive ... he took another exit to the roundabout ... in the meantime crowds built up ... The police tried to keep them calm.

"The situation carried on like this until a plain-clothes police officer with no identification at all came and smashed the window of Besigye's car with a hammer and sprayed pepper right into Besigye's face where he was sitting. A few minutes later Besigye came out of the car clutching his face, obviously trying to breathe. He was grabbed and thrown at the back of a police pickup truck and driven off."

Besigye's bodyguards were dragged from the vehicle and severely beaten, the Reuters news agency reported.

The protests - dubbed "walk to work" in solidarity with Kampala residents who cannot afford public transport as a result of high fuel prices - have been joined by several opposition politicians, one of them still in detention.

President Museveni, in power since 1986, blames drought for high food costs and soaring global oil prices for surging local fuel costs, and has warned Besigye that his protests will not be tolerated.

Besigye told a crowd at a roadblock: "The government is failing to respond to popular discontent in this country. We are not asking for a regime change ... People of Uganda are expressing discontent with conditions in Uganda. Thing is, I am not setting out to be a martyr, I'm simply asserting my citizen's rights."

Source: Al Jazeera and agencies