The State Department on Thursday ordered family members of American government employees working at the United States Embassy in Caracas to leave the country and gave the employees the option to join them before a controversial vote to begin rewriting Venezuela’s Constitution.

The State Department said it had made the decision, along with an expanded travel warning, “due to social unrest, violent crime and pervasive food and medicine shortages” in Venezuela.

The warning comes as the United States and Venezuela approach a showdown over a vote scheduled for Sunday that could lead to a restructuring of Venezuela’s government.

President Nicolás Maduro has ordered the creation of a new body, known as a constituent assembly, which would rule above all other government branches for a period of time in which it would also rewrite the Constitution. Critics of the plan, including the Trump administration, describe the vote as a power grab that would lay the groundwork for a dictatorship.