The United States is warning the Venezuelan government of Nicolas Maduro not to take action against opposition leader Juan Guaido, who plans to return home on Monday.

Guaido has urged supporters to stage huge demonstrations coinciding with his arrival from a Latin American tour as a way to pressure Maduro to resign as president. Workers early Monday were setting up a stage in a Caracas plaza where demonstrators plan to gather.

U.S. National Security Adviser John Bolton tweeted that threats or action against Guaido "will be met with a strong and significant response from the United States and the international community."

The United States and about 50 other countries recognize Guaido as the rightful president of Venezuela. Maduro says he is the target of a U.S.-backed coup plot.