TORONTO - The Ontario Court of Appeal has reduced the sentence of a Toronto man who tried to send nuclear devices to Iran by three months.

Mahmoud Yadegari, 36, was sentenced to four years and three months in jail last July.

With double credit for time served, the sentence amounted to 20 more months behind bars.

Yadegari was arrested in April 2009 after a joint eight-week investigation by the RCMP and the U.S. Department of Homeland Security.

The Iranian-born businessman used a small company operated out of his Toronto home to try to export devices to Iran that can be used to build nuclear weapons.

In a decision released on Tuesday, Justice Cronk wrote that she dismissed Yadegari's appeal.

"The trial judge correctly emphasized that general deterrence was of 'paramount importance,' given the potential harm involved in the appellant's offences," writes Cronk.

"She held that the sentence imposed should promote a sense of responsibility in the offender, and acknowledge the potential harm to the global community. I agree," she adds.

Yadegari, who now has roughly nine-and-a-half months left to serve, tried to export two of 10 pressure transducers he purchased from a U.S. company to Iran via Dubai.

The hand-sized instruments convert pressure measurements into electrical signals for computers and other electronic devices. They have benign applications but can be used in the enrichment of uranium for nuclear weapons.

Iran insists it is enriching uranium to produce nuclear energy for civilian purposes. But the United States and some European countries accuse Tehran of secretly seeking to build nuclear weapons.

Yadegari is believed to be the only Canadian ever charged under the United Nations Act.

He was also charged under the Criminal Code, the Customs Act and the Export and Import Permits Act, as well as provisions in Canada's Nuclear Safety and Control Act.

Yadegari is a Canadian citizen who emigrated from Iran in 1998.