Zakka, an information technology expert, was invited to Iran by a government official a year ago, but then disappeared after attending a conference in Tehran.

State media announced in November that he had been detained by Iran's powerful Revolutionary Guards, and reported that he had ties to U.S. military and intelligence services.

Zakka's supporters and his U.S. lawyer Jason Poblete have said that he is innocent of any wrongdoing.

"Nizar doesn't recognize this process," Poblete said in a telephone interview. "He was there at the invitation of the Iranian government, and he was pulled over on the side of the road by a bunch of men. He's been treated as a hostage ever since."

Poblete said Zakka had learned of his verdict last Wednesday, and his Iranian lawyer was told on Sunday.

"It's 10 years in prison and a $4.2 million" fine, Poblete said of the 60-page verdict. The Virginia-based lawyer said he has not seen the document but was informed of its contents by Zakka's Iranian lawyer.

Zakka was charged under Article 508 of Iran's penal code, Poblete said. The code states that anyone found cooperating with a foreign state against the Islamic Republic of Iran faces a prison sentence of up to 10 years.

Iran's vice president for women and family affairs, Shahindokht Molaverdi, invited Zakka to attend a conference on women's entrepreneurship in September 2015, according to a copy of a signed letter from Molaverdi provided by Poblete.

Amnesty International said last week that Zakka's health was deteriorating in his detention in Tehran's Evin Prison but authorities were denying him medical care.

In a statement, Poblete called on U.S. officials to use the visit by Iranian President Hassan Rouhani to the annual United Nations General Assembly meeting in New York this week to ask for Zakka's unconditional release.

(Reporting by Yeganeh Torbati in Washington and Bozorgmehr Sharafedin in Dubai; Editing by Daniel Bases)