ISNA named the scientist as Darioush Rezaie, 35, a university teacher who held a PhD in physics. It was unclear whether he was part of Iran's nuclear enrichment program. Enriched uranium can be used for civilian nuclear purposes, but also to build atomic bombs.

Deputy Interior Minister Safarali Baratlou said it was unclear whether Rezaie was a nuclear scientist, Iran's Labor News Agency ILNA reported. "Police investigations are continuing ... Nobody has been arrested so far," Baratlou told ILNA.

The state news agency IRNA also reported the assassination but gave different details. Officials were not available for comment.

"Rezaie was a PhD student in electronics ... He was assassinated in front of his child's nursery in Bani Hashem street," IRNA said, quoting an unnamed official. "His wife, who was wounded in the attack, has been hospitalized."

There was no immediate claim of responsibility. Several nuclear scientists have been assassinated in Iran in the past few years, and in November one Iranian scientist was killed and one was wounded in Tehran.

Iranian officials and media have blamed Israel, which Tehran calls "the Zionist regime," and the United States for the killings.

In the past few months, the Islamic Republic has arrested a number of alleged "nuclear spies" and ordered its citizens not to leak information to foreign secret services.

Reuters