The Iranian judiciary has indicted 18 suspects on charges of involvement in the killing of nuclear scientists, according to a news agency.
Since 2010, at least five Iranian nuclear scientists, including a manager at the Natanz enrichment facility, have been killed.
Tehran has accused Israel's Mossad, the CIA and Britain's MI6 of being behind the assassinations.
The US and Britain have denied the allegations but Israel has not commented.
A report by the semi-official Mehr agency quotes Tehran chief prosecutor Abbas Jafari as saying authorities have issued indictments against the 18 suspects and they will go trial in coming months. He gave no other details.
In 2012, Iran hanged a man who was sentenced to death for the 2010 killing of a nuclear physicist.