A Venezuelan opposition leader is demanding that President Hugo Chavez explain accusations of close ties between his government and Colombian rebels.

Opposition leader Manuel Rosales says the Venezuelan leader has not adequately responded after the international police agency Interpol endorsed the authenticity of computer files that Colombia says it seized from a rebel camp.

The documents indicate Chavez's government sought to finance and arm the leftist rebels. And Interpol says its forensic tests found Colombia did not tamper with the documents.

Chavez calls it a "big lie" and insists he hasn't sent money or arms.

But Rosales said on Friday that Chavez should "clear up" the apparently intimate ties.