A lawyer for a prominent Turkish businessman says U.S. charges that his client dealt illegally with Iran are "very defensible."

Attorney Ben Brafman spoke outside court Wednesday after entering a not-guilty plea on behalf of Reza Zarrab. Zarrab is being held without bail. The 33-year-old resident of Turkey was arrested last month in Miami.

Zarrab is well-known in Turkey, partly because he's married to Turkish pop star and TV personality Ebru Gundes. In 2013, Zarrab was arrested in a Turkish government corruption case. He maintained his innocence, and the charges were dropped.

In the U.S., Zarrab is charged with conspiring to process hundreds of millions of dollars' worth of financial transactions for Iranian businesses or Iran's government. Authorities say those transactions are banned by U.S. and international sanctions.