Ugandan police fired tear gas at rock-throwing protesters and briefly detained a top opposition leader Tuesday during renewed demonstrations over rising food and fuel prices.

Authorities arrested Kizza Besigye after he left his home outside the capital, Kampala to take part in the so-called “walk to work” demonstrations. Besigye was later released and driven back home.

Protesters gathered in Kasangati suburb, near Besigye's home, clashed with police who fired tear gas and rubber bullets to disperse the crowd.

Also Tuesday, authorities said 12 opposition supporters who were arrested Sunday have been charged with treason. Police originally accused them of planning disruptive activities.

The opposition group Activists for Change has called for a new round of walk-to-work protests this week, despite government warnings against such demonstrations. Authorities used force to stop similar protests in April and May.

Besigye was arrested several times during those protests.

Opposition groups have blamed the policies of President Yoweri Museveni for rising food and fuel costs. Mr. Museveni has blamed skyrocketing prices on drought and the global oil market.