The United States has warned that Maduro regime in Venezuela that it would be a “terrible mistake” to arrest opposition leader Juan Guaidó, as political tensions in the crisis-stricken country continue to mount.

Guaidó, a 35-year-old opposition leader, was appointed as Venezuela’s legitimate president in January by the National Assembly, a move that has since energized the country’s opposition as they attempt to remove the Maduro regime from power.

The decision to appoint Guaidó has since been recognized by the countries around the world, although there now remain concerns for his safety at the hands of the Maduro regime who have previously imprisoned hundreds of opposition activists, including the leader of Guaidó’s Popular Will party, Leopoldo Lopéz.

“We hold former President Maduro and those surrounding him fully responsible for the safety and welfare of interim president Juan Guaidó and his family,” said State Department spokesman Robert Palladino on Thursday. “It would be a terrible mistake for the illegitimate Maduro regime to arrest Juan Guaidó.”

Over recent months, the U.S. has stepped up its efforts to remove the Maduro regime from power, beginning with recognizing Guaidó as the country’s president, a move since followed by the majority of Western democracies. As well as lending support to the opposition, the Treasury Department has also imposed a fresh range of sanctions on the regime’s vital oil industry, as well as personal sanctions against senior socialist officials.

“The United States government, at all levels, remains firm in its resolve and support for the people of Venezuela and Interim President Juan Guaidó,” Secretary of State Mike Pompeo said Thursday. “We look forward to resuming our presence once the transition to democracy begins.”

Meanwhile, the State Department also released a travel warning this week advising American citizens not to travel to Venezuela under any circumstances.

“Do not travel to Venezuela due to crime, civil unrest, poor health infrastructure, and arbitrary arrest and detention of U.S. citizens. Some areas have increased risk… The safety and security of U.S. citizens is our highest priority,” the State Department advisory read.