Colombia has rejected accusations by Venezuelan President Hugo Chavez that its security forces entered Venezuela to capture a left-wing rebel leader.
Rodrigo Granda was one of Colombia's most wanted
Colombian Defence Minister Jorge Alberto Uribe told local radio none of his country's security forces had violated Venezuelan territory.
Mr Chavez said on Sunday he had proof that the Colombians were lying and that Rodrigo Granda was captured in Caracas.
Mr Granda is described as the Farc rebels' unofficial foreign minister.
The Farc, or Revolutionary Armed Forces of Colombia, is the main leftist rebel group in Colombia.
Mr Chavez said mobile phone records showed he was snatched from a city street on 13 December and smuggled across into Colombia.
The Colombian authorities, however, maintain he was arrested a day later in the Colombian city of Cucuta near the Venezuelan border.
"Neither the Colombian army nor the police violated Venezuelan territory or the territory of neighbouring countries," Mr Uribe said, quoted by the Associated Press news agency.
Mr Chavez said he was investigating reports that members of Venezuela's own security forces may have colluded in the alleged kidnapping.
He had smelt a rat from the beginning, he added.
According to President Chavez, a call was registered to Mr Granda's mobile phone in central Caracas just minutes before the reported kidnapping incident.
Another call was recorded some hours later from the Venezuelan side of the frontier.
"There is no doubt, the Colombian police are lying. When they say Granda was captured in Cucuta, the Colombian police are lying," Mr Chavez said.
He suggested they had probably also been lying to the Colombian President, Alvaro Uribe, and vowed to take up "energetically" any violation of Venezuelan sovereignty.