CORPUS CHRISTI, Texas (Reuters) - Venezuela has told dozens of expatriate staff working for Citgo Petroleum Corp in the United States that they must return to Caracas by the end of February, people familiar with the matter said, following U.S. sanctions aimed at forcing socialist President Nicolas Maduro from power.

Citgo is owned by Petroleos de Venezuela, or PDVSA, currently controlled by the state and Maduro, who won re-election last year in a contest widely regarded as fraudulent.