The Treasury Department announced sanctions against several key Venezuelan officials Wednesday.

The announcement comes as Venezuelan President Nicolas Maduro is scheduled to oversee an election on Sunday that will allow him to rewrite the constitution, a move that is viewed by his opposition as a power grab.

Four of the senior officials sanctioned are involved in these elections. All of the 13 sanctioned current and former officials will not be allowed to do business with American individuals or businesses and will have whatever assets they currently hold in the U.S. frozen.

Other sanctioned individuals include current and former members of Venezuelan military or law enforcement groups that the Treasury Department have identified as being responsible for the brutal responses to anti-government protests. The Treasury Department cited opposition estimates that 15,000 civilians have been wounded in protests, and that there are 431 political prisoners in detention.

The Treasury’s Office of Foreign Assets Control also targeted four current and former officials of state institutions that have been identified as corrupt. Two of these individuals are associated with the state-owned oil company, Petroleos de Venezuela, from which around $11 billion went missing across a ten-year span.

“As President Trump has made clear, the United States will not ignore the Maduro regime’s ongoing efforts to undermine democracy, freedom, and the rule of law,”  Treasury Secretary Steven Mnuchin said in a statement.  “As our sanctions demonstrate, the United States is standing by the Venezuelan people in their quest to restore their country to a full and prosperous democracy.  Anyone elected to the National Constituent Assembly should know that their role in undermining democratic processes and institutions in Venezuela could expose them to potential U.S. sanctions.”