Washington has rejected Iran’s allegations of U.S. involvement in Tuesday’s bombing that killed professor Massoud Ali-Mohammadi near his home in the Iranian capital as absurd.

Iranian officials and state media described the slain man as a nuclear scientist, but a spokesman said he did not work for the Atomic Energy Organization at the center of Iran’s disputed nuclear program.

Iran’s influential parliament speaker, Ali Larijani, said a U.S.-based pro-monarchy group had claimed responsibility for the attack, adding the group was controlled by the CIA. Iran’s Fars News Agency on Tuesday said such an exile group had claimed the bombing in a statement, without saying how it obtained it.

“An American-based monarchy group … claimed responsibility for this terrorist act,” Larijani said, the state broadcaster reported. “Maybe the CIA and the Zionist regime (Israel) thought they can mislead us with such an absurd statement.”

“We had clear information several days ago that the intelligence apparatus of the Zionist regime and the CIA wanted to implement terrorist acts in Tehran,” he said.

Using such a “rootless group” as a cover was a new “disgrace” for U.S. President Barack Obama, Larijani said. “Why do you host this terrorist group in America?” he asked.

via Iran knew Israel, U.S. planned terrorist acts: speaker | Reuters.