Venezuelan President Hugo Chavez threatened on Sunday to cut off oil supplies to the United States if it supports a Colombian military attack on Venezuela and warned Washington to stay out of the crisis.
Chavez broke off diplomatic relations with Bogota on Thursday in response to charges by President Alvaro Uribe that 1,500 Colombian guerrillas had set up camp inside Venezuela and were launching attacks from its territory.
The firebrand leftist leader said that if Colombia were to launch an attack "promoted by the Yankee empire, we would suspend oil deliveries to the United States, even if everybody over here has to eat stones.
"We wouldn't send even a single drop of oil" to the United States, he said.
Venezuela, a member of the Organisation of Petroleum Exporting Countries (OPEC), is South America's largest oil producer and exporter.
Chavez said he had intelligence that "the possibility of an armed aggression against Venezuelan territory from Colombia" was higher than it has been "in 100 years."
"Everything points to the Colombian government, and even more so to the United States - there you have the guilty one, there you have the great instigator," added Chavez, who is highly critical of a US-Colombian military base deal struck last year.
Chavez said Venezuela was ready to repel any aggression from Colombia.
Venezuela's armed forces along the border with Colombia were placed under "maximum alert" by Chavez, to prevent a possible military incursion.
At present, there are some 20,000 troops deployed along Venezuela's 2,000-kilometer (1,250-mile) border with Colombia, according to military officials.
The United States on Friday threw its support behind its key ally Colombia in its latest row with Venezuela, calling Chavez's decision to sever diplomatic relations with Colombia and put border troops on alert "a petulant response" to Bogota's accusations.
Chavez on Sunday hinted at a possible easing of tensions with Colombia when president-elect Juan Manuel Santos replaces Uribe on August 7.
"We must get clear and unambiguous signs that Colombia's new government has real political will to resume the path of dialogue (with Venezuela) without any tricks," Chavez wrote in an op-ed piece published in several newspapers.
Santos, who is on a tour of Latin America, has refused to comment on the crisis, referring the matter to the outgoing president.
Chavez also announced on Sunday he would cancel a planned trip to Cuba in light of the crisis.
He was to attend on Monday in Havana the 57th anniversary of Fidel Castro's rebel attack on the Moncada barracks that kicked off the revolution that brought him to power in 1959.
Venezuela's exports to the United States are almost entirely comprised of oil.
Last year oil exports alone reached 27.12 billion dollars, accounting for 96.5 per cent of all products exported to the United States, which remains the number one consumer of Venezuelan oil.
However that was a steep drop compared to 2008, when the South American country exported 51.40 billion dollars worth of goods to the United States, the Venezuelan American Chamber of Commerce and Industry said earlier this year.
US imports in Venezuela also decreased in 2009, coming in at 9.36 billion dollars - 27.7 per cent less than the previous year.
In 2008, total trade between the two countries had reached a historical high of 64 billion dollars with the bulk of that amount - 76.4 per cent - corresponding to oil sales.
Oil accounts for around 90 per cent of revenue in Venezuela, South America's top exporter of crude oil.