Iran says about 20 suspects have been arrested for alleged links to assassinations of Iranian nuclear experts that Tehran claims is part of covert operations led by Israel.
Sunday's remark by Intelligence Minister Heidar Moslehi is the first official number on the detentions. Last week, Iran announced it had made arrests linked to the slayings.
Moslehi claims the suspects moved between Iran and Israel through a neighboring country. He did not name the country, but Iran has accused Azerbaijan of harboring terrorists linked to Israel.
At least five Iranian nuclear experts have been killed since 2010. The U.S. and Britain have denied any roles, but Israel has remained silent on Iran's accusations. In May, Iran hanged a man convicted in the killing of a nuclear physicist in early 2010.