The suspects are accused of assassinating a physicist at Iran's Atomic Energy Organisation (AEOI) and a deputy director at the Natanz uranium enrichment facility using magnetic bombs that were attached to the vehicles they were in.

Tehran has accused Israel and the United States of plotting the killings to set back its nuclear program. Washington has denied any U.S. role, while Israel has declined to comment.

AEOI physicist Majid Shahriari was killed in 2010 and Mostafa Ahmadi-Roshan in January this year.

"The key perpetrators of the assassinations...were identified and, in a series of rapid and authoritative operations, were arrested and transferred to detention facilities," read a statement from the intelligence ministry, published by Press TV's website.

Iran denies Western accusations that it is developing a nuclear weapons capability, saying it simply wants to generate electricity and radio isotopes for medical treatment. Tehran is due to hold talks with world powers in Moscow on June 18-19.

At least four scientists associated with Iran's nuclear program have been assassinated since 2010 and a fifth - Fereydoun Abbasi Davani, now head of the AEOI - was wounded.

Last month, authorities hanged 24-year-old Jamal Fashi for the murder of one of the scientists, Massoud Ali-Mohammad, in January 2010.

Iran said Fashi confessed to travelling to Tel Aviv to receive training from Israeli intelligence agency Mossad before returning to Iran to plot the assassination, details that were greeted with derision by Israel.

Israel has a policy of not commenting on the allegations but an unnamed Israeli source previously said the daylight killings had provoked panic in the scientists' colleagues which hindered Iran's nuclear progress.

*Reporting By Marcus George; Editing by Pravin Char