Colombia is taking a tougher tone with neighboring Venezuela by calling for the release of a jailed opposition leader.

Since taking office in 2010, President Juan Manuel Santos has been reluctant to criticize Caracas, hoping to avoid a return of tensions that had the countries hinting at a possible armed conflict in 2008.

Colombia's foreign ministry broke with its hands-off policy late Monday and became the first South American nation to call for the release of Leopoldo Lopez, who has been jailed for 11 months on charges of instigating violence at anti-government protests.

Venezuela didn't wait in responding. In a statement Tuesday the socialist government repudiated Colombia's position, which it said conspires against the country's democracy and marked a "dangerous step backward" in bilateral relations.