Americans who work for non-US companies located outside of the United States and Venezuela have until March 29 to conduct "certain maintenance or wind-down transactions," according to the notice dated Jan. 31 and posted on the department's website overnight.

The department's Office of Foreign Assets Control also addressed other issues related to looming US sanctions on Caracas' state-run oil company aimed at putting pressure on President Nicolas Maduro who the Trump administration seeks to oust from power.

The notice offers more details about transactions that are allowed and prohibited, and offers guidelines on bondholders' rights regarding US refiner Citgo Petroleum as well as details on what constitutes "maintenance" transactions.

US officials imposed sanctions on PDVSA this week, a move Maduro has called illegal.

The global oil industry has since sought to sort out the large-scale sanctions, which froze the assets of the company and require US firms to pay for oil using accounts controlled by the country's opposition party head and self-proclaimed interim president, Juan Guaido.

US President Donald Trump and his administration have thrown their support behind Guaido.