Venezuelan President Nicolas Maduro on Wednesday accused former Colombian President Alvaro Uribe of plotting to assassinate him in cohorts with Colombia’s US ambassador Francisco Santos, and exiled Venezuelan opposition leader Lester Toledo.

It was not the first time Maduro, a socialist, accused politicians from neighboring Colombia of plotting against him, as relations between the two countries deteriorate amid an economic crisis in Venezuela that has prompted more than one million migrants to settle in Colombia.

During a state television broadcast on Wednesday evening, Maduro gave a detailed account of how the three plotted the attack from “a bunker” in a house belonging to Uribe, a right-wing leader who has been an outspoken critic of Maduro and his predecessor and mentor, the late former President Hugo Chavez.

Colombian Foreign Minister Carlos Holmes denied the allegation in a post on Twitter, saying the government “rejects the delirious and slanderous accusations by the dictator Maduro against two Colombians who have dedicated their lives to serving democracy.”

A press advisor to Uribe did not respond to a request for comment. Toledo, who is based in Colombia, has been designated by Venezuelan opposition leader Juan Guaido as his international coordinator for efforts to bring in humanitarian aid. He could not be reached for comment.