CARACAS (Reuters) – A Venezuelan court on Friday ordered that six executives from U.S. refiner Citgo should stand trial on charges of corruption, defying pressure from U.S. authorities to release for the group that includes naturalized U.S. citizens.

The executives were arrested in November 2017 after being called into a meeting at the Caracas office of Venezuelan state oil firm PDVSA, which owns Citgo. They were accused of crimes including embezzlement and money laundering in connection with a never-concluded refinancing agreement.

A Caracas-based court ruled that the six will remain in jail during trial, Venezuela’s supreme court said on its website.

Family members of Jose Luis Zambrano, Alirio Zambrano, Jorge Toledo, Tomeu Vadell, Gustavo Cardenas and Jose Pereira have asked the U.S. government to intervene, citing health concerns for the men.

U.S. Vice President Mike Pence and two senators have called for their release

Venezuelan Nicolas President Maduro in 2017 began a corruption crackdown at PDVSA that led to dozens of executives being jailed, including former Citgo and PDVSA President Nelson Martinez. Martinez died in custody in December.

(This story has been refiled to add full reference to Maduro in 6th paragraph).