Iran’s influential parliament speaker, Ali Larijani, said a U.S.-based pro-monarchy group had claimed responsibility for the attack, adding it 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.

In Washington on Tuesday, a U.S. intelligence official said the CIA played no role in the bombing in Tehran.