"During the visit of Iraqi Prime Minister Nouri al-Maliki [to Iran in June] I told him about an assassination attempt [in March] and reiterated that I would make public all the details if the Americans denied their involvement," Ahmadinejad told a news conference in Tehran.
He mentioned the assassination attempt for the first time last week and said only changes to his schedule had foiled the plot. However, the West and even some inner Iranian circles dismissed his allegations.
"I raised the assassination issue, and the main culprit, which is the U.S. government, could not disprove my words...we all know why," he said on Wednesday.
Ahmadinejad, 51, who became president in 2005, is a strong critic of the West and has also called for Israel "to be wiped off the map."
Western nations have accused Iran of pursuing a secret nuclear weapons program. Iran has denied the allegations, saying it needs nuclear energy for civilian purposes.
The Bush administration considers Iran to be the world's leading state supporter of terrorism.
