Updated

Protesting coffee growers, farmers and truckers are blockading Colombian highways for a third day in various regions, with some protesters pelting riot police with rocks and homemade explosives.

Police director Gen. Rodolfo Palomino reports at least 61 arrests in the disturbances that began Monday.

The more than 30,000 protesters have an assortment of demands: Truckers want cheaper gasoline. Potato and onion growers are demanding lower prices for fertilizer. Coffee farmers want a government subsidy extended.

Many of the farmers object to free trade agreements signed with the United States and European Union that they say threaten their livelihoods.

The protests do not affect vital industries. But they are a major challenge for President Juan Manuel Santos.

He says he won't negotiate until blockades are lifted.