Iranian President Mahmoud Ahmadinejad was unharmed when a homemade explosive went off near his convoy during a visit to the city of Hamedan on Wednesday,a source in his office said. But the state media said only a firecracker had been set off by an young man excited to see the President and a police chief called news of an attack a big lie spread by foreign media. The source from Ahmadinejads office said the Presidents convoy was targeted as he was traveling from Hamadan airport to give a speech in a sports arena. The President was unhurt,but others were injured and one person was arrested,he said. There was an attack this morning. Nothing happened to the Presidents car, the source said. Investigations continue. to find out who was behind it. Ahmadinejad appeared on live Iranian television at the sports stadium. He looked unperturbed and made no mention of any assault. State news agency IRNA said an excited young man from Hamadan exploded a firecracker in order to express his happiness. It did not cause any disturbance among the crowd which was giving a warm welcome to the President. Some foreign media tried to take advantage of this event,in line with their goals, IRNA said. Some domestic media called this harmless firecracker a grenade explosion and some called it a hand-made grenade and this led to some ambiguity. Irans Deputy Police Chief Ahmadreza Radan said foreign news media wanted to exploit the situation. Its a big lie that some foreign media published and wanted to spread, Fars quoted him as saying. During a speech to a conference of expatriate Iranians in Tehran on Monday,Ahmadinejad had said he believed he was the target of an assassination plot by Israel. The stupid Zionists have hired mercenaries to assassinate me, he said. Several armed groups opposed to the government are active in Iran,mostly made up of ethnic Kurds in the northwest,Baluch in the southeast and Arabs in the southwest.