A U.S. court has held Iran accountable and ordered it to pay more than $1.4 billion in damages to the family of a former Federal Bureau of Investigation agent who went missing during a visit to the country's Kish island in March 2007.

Robert Levinson, a Jewish American citizen, was eventually declared dead by the U.S. government and the Iran government denied knowledge of his whereabouts.

Levinson was believed to have been kidnapped by Iran while on an unauthorized Central Intelligence Agency mission to the Iran island that year.

Iran President Hassan Rouhani indicated a willingness to cooperate with the American government six years later to return Levinson to the U.S. but nothing meaningful came from that.

The Levinson family and the U.S. government now believe the FBI agent perished in the custody of Iran authorities - something it denies.

U.S. District Judge Timothy Kelly said the court endorsed a special expert's guidance that Levinson's family be given $107 million in compensatory damages. Kelly also granted $1.3 billion in punitive damages.

Iran state news media and officials didn't immediately acknowledge the decision.

According to Levinson's family, the judgment is the "first step in the pursuit of justice for Robert Levinson," whom they describe as an American patriot who was kidnapped and subjected to unimaginable suffering for more than 13 years," Reuters quoted the family as saying.

The family said Judge Kelly's decision wouldn't bring the former FBI agent home but "we hope that it'll serve as a warning" against taking hostages, RepublicWorld reported. The Islamic republic, the family added, faced no consequences for its actions until now.

A representative for Iran's mission to the United Nations didn't immediately respond to requests for comment.

Tensions between the U.S. and Iran continue because of U.S. President Donald Trump's pressure over Iran's nuclear program.