DUBAI, United Arab Emirates (AP) — The U.S. Embassy in Abu Dhabi is raising new concerns about the health of a jailed American businessman on hunger strike in the United Arab Emirates.

Zack Shahin has been held in Dubai for more than four years on corruption allegations, but has yet to stand trial. He has denied any improprieties and began a hunger strike on May 14 to demand authorities hear his case.

Embassy official L. Victor Hurtado said in a statement Friday that "obviously there are serious concerns about Mr. Shahin's health" after more than six weeks without food. Hurtado is the U.S. Embassy's Chargé d'Affaires and visited Shahin this week.

He urged authorities to release Shahin on bail and consolidate several separate pending cases against him.

UAE officials had no immediate comment.