By Elias Biryabarema and Justin Dralaze
KAMPALA (Reuters) - Military police fired tear gas on Thursday to disperse a crowd of more than 1,000 marching to the center of the Ugandan capital Kampala in protest against steep rises in food and fuel prices, Reuters witnesses said.
Opposition leader Kizza Besigye, President Yoweri Museveni's closest rival in February elections, marched with the demonstrators, who had gathered in a Kampala suburb and defied police attempts to scatter them before they reached the city center.
Opposition and civil society groups launched their first "walk to work" protest against steep rises in the cost of living on Monday but it was swiftly stifled by police, and opposition leaders were detained.
The groups had vowed to continue protesting every few days and the march on Thursday was their second demonstration.
At one stage police vehicles stopped firing tear gas at the protesters and escorted them toward the city center, Besigye among them.
But the protesters were then dispersed by beefed up security forces, firing more tear gas.
Prices have been rising in Uganda because drought reduced food production in many parts of the country and higher fuel prices increased transport costs, pushing up food prices further in urban areas.
Uganda's consumer price index rose 4.1 percent in March from February, pushing the year-on-year inflation rate up for a fifth successive month to 11.1 percent from 6.4 percent a month earlier.
Food prices jumped 11.9 percent in March from February, hitting the poorest Ugandans severely, as they spend the highest proportion of their income on basic goods such as food.
Besigye was charged with inciting unrest and released on bail after Monday's protest.
After the president election in February, Besigye called for peaceful protests against Museveni's 25-year-old rule, saying the poll had been rigged, but they failed to get off the ground.
(Reporting by Elias Biryabarema; Editing by George Obulutsa and Tim Pearce)