-sources@ (Adds background, no immediate comment from State Department)
LONDON, May 23 (Reuters) - The United States told some large trading houses this week they should stop trading jet fuel with Venezuela or face sanctions, ratcheting up pressure aimed at removing Venezuelan President Nicolas Maduro from power, according to two industry sources.
According to the two sources familiar with the calls to several large Swiss- and British-based trading houses, which were made by U.S. State Department officials, the move is aimed at restraining commercial and military flights in Venezuela.
The U.S. officials said diesel trade with Venezuela was still considered legal for humanitarian reasons.
The U.S. Department of State did not immediately respond to a request for comment.
The pressure, part of Washington's stalled effort to oust Maduro in favor of opposition leader Juan Guaido, follows similar requests made in March. U.S. officials told global trading houses and oil refiners then to reduce dealing with Venezuela or face sanctions themselves, even if the traders were not prohibited by U.S. sanctions.
U.S. officials have been trying to end deliveries of gasoline and refined products used to dilute Venezuela's heavy crude oil to make it suitable for export.
As the United States boosts oil and natural gas output, it has increasingly been using its energy clout. At an energy conference in Houston in March, U.S. Secretary of State Mike Pompeo laid out a vision of working with energy firms to isolate Iran and Venezuela. (Reporting by Dmitry Zhdannikov and Julia Payne; additional reporting by Timothy Gardner in Washington Editing by Alexandra Hudson and Marguerita Choy)