Iran blamed Israel for a drone attack on a military factory near the central city of Isfahan, the semi-official ISNA news agency said on Thursday, vowing revenge for what appeared to be the latest episode in a long-running covert war.
In a letter to the U.N. chief, Iran's U.N. envoy, Amir Saeid Iravani, said primary investigation suggested Israel was responsible for the attack on Saturday night.
"Iran preserves the right to give a firm response whenever and however it feels necessary," Iravani said in the letter, adding, "This action undertaken by Israel goes against international law."