President Donald Trump on Wednesday warned U.S. citizens against traveling to Venezuela amid the political crisis there over control of the government, as the United States and other nations have recognized Venezuelan President Nicolas Maduro’s rival Juan Guiado, Reuters reports.

“Maduro willing to negotiate with opposition in Venezuela following U.S. sanctions and the cutting off of oil revenues. Guaido is being targeted by Venezuelan Supreme Court. Massive protest expected today. Americans should not travel to Venezuela until further notice,” Trump wrote on Twitter.