An Iranian nuclear scientist was killed by a magnetic bomb placed on his car, an attack Tehran's deputy governor blamed on Zionists back by the U.S. and Israel. The state news agency said the scientist âsupervised a department at Natanz Uranium Enrichment Facility.âWhile the U.S. has denied the allegations, Israel's chief miltary spokesman said that though he doesn't know who did it, he's "not shedding a tear."Tensions between Iran, the U.S., and Israel have been high for months, but they were ratcheted up yet again last week when the country announced its plan to carry out enrichment work in a fortified underground facility near Qom.