A peaceful protest of 30,000 turned violent when young people wearing masks opted to show their support for farmers by throwing bombs and bricks in city streets. At least four people were arrested and 12 police officers injured in the melee in downtown Bogota. Red Cross officials said 10 civilians were hurt.

The 45,000 farmers, coffee growers and truck drivers who have blocked highways and battled with riot police since last week say their business is simultaneously hurt by protectionist tariffs on fertilizer, which make their product expensive compared to other countries, and free trade promoted by their government. 

Yes, they say protectionism is hurting them when free trade isn't. They could fit right into a gathering of Seattle college students.

Rioting breaks out in Colombia's capital as president acknowledges 'a storm' is battering farm sector By Cesar Garcia, The Associated Press