Venezuelan opposition leader Maria Corina Machado urged the international community on Wednesday to step up pressure on hardline President Nicolas Maduro to quit.
Machado has been in hiding in Venezuela since August, following a presidential election in July that Maduro claims to have won.
The opposition insists that its candidate, Edmundo Gonzalez Urrutia, won the vote by a landslide. He is currently in exile in Spain.
Unrest following the vote claimed 27 lives and saw more than 2,400 arrested on charges of "terrorism" for taking part in protests.
"We need the international community, international justice to act" and make Maduro and other Venezuelan officials accountable, Machado told a conference in Prague.
She was speaking two days after winning a human rights prize awarded by the Council of Europe and named after Prague-born dissident playwright-turned-president Vaclav Havel.
Machado urged the international community to step up pressure on the pillars of Maduro's power including the army and the police.
"We need to let them know that they will be held accountable," she said.
The world should continue to recognise Urrutia as the president-elect and help cut Maduro off from "illicit financial resources", Machado added.
"Those come from narco-trafficking and drug-trafficking. They come from illegal mining and smuggling ... gold and even trafficking of human beings.
"And European countries can do a lot to help close those flows immediately," Machado said.
The West should make Venezuela a priority as "this tragedy goes well beyond our borders", she added.
"The regime is destabilising the whole region," Machado said. It was opening the door for countries like Russia, Iran, Cuba or Syria to wield influence in Latin America, she added.
"Maduro has never been as weak and as isolated as he is today, and we need to put more pressure on him because this is the chance we've been fighting for for two and a half decades."