An Iranian official denied reports that President Mahmoud Ahmadinejad
survived an attack with a homemade explosive device on his motorcade during a visit to the western city of Hamadan on Wednesday.
The official explained that a "firecracker" caused the explosion near Ahmadinejad's convoy.
"It was a firecracker, and a statement will be released soon," the source said.
Iran's Arabic-language Al-Alam TV reported that the firecracker was set off to cheer the president.
Earlier, an official Iranian source said Ahmadinejad's convoy was targeted as he was traveling from Hamadan's airport to give a speech in a local sports arena and the president was unhurt but others had been injured in the blast.
One person had been arrested, the presidency source said. There was no immediate claim of responsibility for the attack.
The populist, hard-line Ahmadinejad has accumulated enemies in conservative and reformist circles in the Islamic Republic as well as abroad.
Al Arabiya television said an attacker had thrown a bomb at Ahmadinejad's convoy before being detained.
Dubai-based Al Arabiya television cited its own sources as saying the bomb had hit a car carrying journalists and presidential staff.
Ahmadinejad appeared on live Iranian television at a sports stadium in Hamadan. He was apparently well and made no mention of any assault.
Ahmadinejad speaks after assassination attempt
Earlier this week Iranian news outlets quoted Ahmadinejad as saying that Israel
was trying to assassinate him. In a speech delivered on Monday, the Iranian president said, "The stupid Zionists have hired mercenaries to assassinate me. Look how hopeless they are."
Ahmadinejad and supporters in Hamadan
Last year Iran's intelligence minister also claimed Israel was trying to kill Ahmadinejad. According to him, "Zionist" elements had met in Egypt and Paris with members of the Iranian opposition group "Mujahideen Khalq" in order to plan an assassination.
In November the Iranian Intelligence Ministry said it succeeded in thwarting a "plot to kill a senior regime official." It was apparently referring to Ahmadinejad.
In 2008 Ahmadinejad's aide said another plot to assassinate the president during his visit to Italy was foiled.
AP, Reuters contributed to the report