Venezuela has raised the stakes in its diplomatic dispute with Colombia after Hugo Chávez, Venezuela's president, threatened to sever ties completely with Bogotá and accused the US of engaging in an “imperialist” plot.

Mr Chávez said at the weekend that he would cut relations with the US-backed neighbour and stop all bilateral trade if the government of Alvaro Uribe failed to “apologise” for the capture in December of a Colombian insurgent in Caracas.