Several loud explosions were heard in Iran's capital Tehran and the nearby city of Karaj city early on Saturday, semi-official Iranian media said, adding that the cause was unknown.
Iran's state TV said several strong explosions heard around the capital, but there was no official comment about the source of explosions.
Israel has been planning a response to a ballistic-missile barrage carried out by Iran on Oct. 1, Tehran's second direct attack on Israel in six months.
