Venezuela leader Hugo Chavez severs ties with Colombia
Venezuela has broken off diplomatic relations with Colombia and ordered Colombian diplomats to leave the country by Sunday.
President Hugo Chavez said he had "no choice" after Colombia accused Venezuela of being a haven for guerrillas - a charge he denies.
He said that he was acting "out of dignity" in severing ties.
He also ordered the military to be on maximum alert on Venezuela's border with Colombia.
Venezuelan Foreign Minister Nicolas Maduro said the government was also considering suspending flights and cutting commercial ties with Colombia.
President Chavez made his announcement shortly after a meeting of the Organisation of American States (OAS) in Washington, at which Colombia presented videos, maps and photos to back up its claims that Marxist Farc and ELN rebels have bases in Venezuela.
"We have no other choice but, out of dignity, to totally break our relations with our brother nation of Colombia," Mr Chavez said live on national television as he hosted a visit by Argentina football coach Diego Maradona.
What Colombia may try to prove is that Venezuelan officials are working alongside or at least collaborating with the Colombian rebel groups, which are on international terrorist lists.
If that can be proved it could imply that Venezuela is sponsoring terrorism, something which could bring international sanctions.
At the moment, neither side is prepared to cede anything. However, that may change in two weeks, when Juan Manuel Santos takes over the Colombian presidency.
He has already intimated that he wants better relations with Venezuela and his taking office may defuse what is an extremely tense situation.
He said the photographs shown to the OAS could have been be faked, and insisted that Venezuela was doing everything possible to stop Colombian rebels crossing the border.
"We do not tolerate the Farc in Venezuela," he said, before calling outgoing Colombian President Alvaro Uribe a "mafia boss", a "madman" and a "criminal".
He suggested Mr Uribe could be seeking a conflict with Venezuela before he left office next month.
"Uribe is even capable of setting up a fake camp in one of the jungles on the Venezuelan side to attack it, bomb it and bring about a war between Colombia and Venezuela," Mr Chavez said.
A US official was quoted by AFP news agency as saying that Venezuela breaking ties with Colombia was not a "proper way" to raise concerns.Inspection call
In Washington, Colombian ambassador to the OAS Luis Alfonso Hoyos said the material was clear evidence that about 1,500 Colombian rebels were sheltering at numerous camps inside Venezuela.
His Venezuelan counterpart, Roy Chaderton, ridiculed the Colombian evidence, saying that the photos and videos could have been taken anywhere.
Mr Hoyos demanded that Venezuela fulfil its international obligations to fight terrorism and that it allow an international commission to visit suspect sites.
- March 2008: Caracas sends troops to border after a Colombian raid into Ecuador to kill Farc rebels
- July 2008: Colombia and Venezuela make up after release of Farc hostage Ingrid Betancourt
- November 2009: Venezuela sends 15,000 troops to border after Colombia-US deal on use of Colombia's military bases
- June 2010: Juan Manuel Santos elected President of Colombia. Caracas previously said his election "could lead to war in the region"
- July 16, 2010: Caracas describes as provocation Bogota's announcement that Colombian rebels are sheltering in Venezuela
- July 22, 2010: Colombia presents what it says is evidence for its accusations at OAS meeting. Venezuela breaks off diplomatic relations
"We have the right to demand that Venezuela doesn't hide those wanted by Colombia," he said.
After the meeting, OAS Secretary General Jose Miguel Insulza told reporters that the regional body could not mount an inspection mission without Venezuela's consent.
The issue over whether Venezuela has rebels on its territory has dogged ties between the two South American nations for the past eight years.
But the latest exchange plunges bilateral relations to a new low.
The BBC's Jeremy McDermott in Bogota says it also leaves Juan Manuel Santos, who takes over as Colombia's president from Mr Uribe in two weeks, with a very difficult situation to handle.