U.S. authorities say they are supporting Jamaican investigators with their probe of a U.S. citizen who has been detained at an island airport with a bundle of undeclared cash.

Jamaican authorities say they detained Sohail Muhammad Siddiq last week at the international airport in the northern tourist city of Montego Bay. He had apparently traveled from Dubai.

On Tuesday, a U.S. Immigration and Customs Enforcement spokesman said agents were assisting Jamaican counterparts with their financial crime investigation. ICE spokesman Ross Feinstein says Jamaican authorities told the U.S. agency that the suspect was traveling with more than $400,000 in cash, nearly all of it euros.

Feinstein says the suspect is a naturalized U.S. citizen originally from Pakistan with addresses in both Texas and Illinois.