Taken from reports which appeared first in full on  http://colombia.indymedia.org/ and written by “burromoro” and “el asistente” respectively.

“On Thursday 20 March 150 Ecopetrol workers accompanied by union leaders from the CUT and a number of activists held a protest outside the Ecopetrol offices in Bogota. They sang and chanted against the Uribe Velez government’s support for the war in Iraq, against US intervention and for peace in our country, and also against Chevron-Texaco taking the gas in the Guajira region of Colombia. US flags were burnt and the traffic held up for a while, before the workers returned to work.” (El asistente)

“On Friday the 21st of March there was a march against the bloody genocide in Iraq. Groups like the PST (1), Banderas Negras (2), students, workers and many more who support the right to life gathered in Catastro at 11 a.m. and marched towards the U.S. embassy, displaying our anti war messages and carrying out civil disobedience to open peoples eyes as to what is going on. Earlier on North Americans against the war, local Christian pacifists and a theatre group had all arrived outside the embassy, bringing the total present up to about 200.
We moved slowly in order to tie up the traffic on Calle 26, whistling and applauding as more people joined the march. Squads of riot police were there (SMAD and others) as always, prepared for anything, not realizing it was a peaceful march. Having said that, we were hoping to occupy the pedestrian bridge outside the embassy when we got there, but the robocops prevented us. Onlookers in their apartments or from passing cars raised their arms or beeped in support.
Arriving at Carrera 50 we took up the area behind the embassy, blocking the road so that the traffic would pile up and people would notice us. And three hours after the march had begun we were back on Calle 26 where we blocked the road again for some minutes in order for a little ceremony to round things off for the day. Some people had brought a 6x4 metre large American flag made from newspaper which we poured petrol over. Before burning it a student spoke to those present saying: For some this flag means liberty and democracy but for others bloodshed, fear and destruction. We’re going to burn it so they know we don’t want them in Iraq, or here, or anywhere else in the world.
For 20 seconds people spitted on, trampled on and kicked the flag as it burned. We then dispersed, concerned that one of the riot squads might be round the corner waiting to detain someone, but everyone stuck together in their groups.
In conclusion, more and more people are attending these anti war demos (see Colombia and UK indymedia for reports of others held before and after these), if we can call them that. But we need more people. We’re beginning to make our presence felt - I noticed that everyone near the march waved their hands or showed in some other way that they too were against the war, and that is the main purpose of these marches.” (Burromoro)
Translators notes:
1. PST is I think a Trotskyist group.
2. Banderas Negras is the anarchist Black Flags coordinator comprising different collectives in the city. See  http://geocities.com/coordinadorabanderasnegras