(NewsNation) — As the Trump administration works to take control of oil-rich Venezuela, major U.S. energy companies are speaking out.

In a statement to NewsNation, a spokesperson for Chevron wrote, “Chevron remains focused on the safety and wellbeing of our employees, as well as the integrity of our assets. We continue to operate in full compliance with all relevant laws and regulations.”

Chevron has been operating in Venezuela for over 100 years and is the only major U.S. oil company currently operating in the country. The Houston Chronicle reports that Chevron produces 150,000 barrels of oil per day in Venezuela, about 17% of the country’s overall output. The company has five oil production operations in the country, which are a mix of onshore and offshore.

ConocoPhillips, which is not currently operating in Venezuela, said it is monitoring the situation.

“ConocoPhillips is monitoring developments in Venezuela and their potential implications for global energy supply and stability. It would be premature to speculate on any future business activities or investments,” Dennis Nuss, Director of Media Relations and Crisis, at the company, wrote in a statement to NewsNation.

ConocoPhillips and ExxonMobil left Venezuela in 2007 when then-President Hugo Chávez forced renegotiated contracts with international oil companies, according to NPR.

Early estimates place potential investment opportunities in Venezuela between $500 billion and $750 billion over the next five years.