Mr Chavez sent 15,000 soldiers to the Colombian border last week
Venezuelan President Hugo Chavez has urged his armed forces to be prepared for possible war with Colombia amid growing diplomatic and border tensions.
He said the best way to avoid war was to prepare for it. In response, Colombia said it would seek UN help.
Venezuela blames the tension with its neighbour on closer military ties between Colombia and the US.
Colombia says US forces are there to help in the fight against rebels and drug traffickers.
"Let's not waste a day on our main aim: to prepare for war and to help the people prepare for war, because it is everyone's responsibility," Mr Chavez said during his TV and radio show Alo, Presidente.
Mr Chavez has also ordered 15,000 troops to the border, citing increased violence by Colombian paramilitary groups.
The BBC's Jeremy McDermott in Bogota, Colombia, says that normally such declarations would not cause alarm, but because of the current tensions there are fears of a possible spark on the border which could lead to further violence.
In response to Mr Chavez's comments, Colombian President Alvaro Uribe said his government would seek help from the UN Security Council and also the Organization of American States.
"Colombia has not made nor will it make any bellicose move toward the international community, even less so toward fellow Latin American nations," a statement by Mr Uribe said.
Ties between Colombia and Venezuela have been frozen since July when Bogota said it would let the US army use its military bases for anti-drugs operations.
The agreement has caused alarm among some of Colombia's neighbours, who object to an increased US military presence in the region.
When news of the deal first broke in August, Mr Chavez warned that "winds of war" were blowing across the continent.