Iranian President Mahmoud Ahmadinejad snapped back at US President George W Bush on Monday, saying he had no time to listen to his warnings.
Bush warned Ahmadinejad on Saturday, before the Iranian president's landmark visit to Iraq, to "stop exporting terror."
He accused Iran of fomenting the violence in Iraq and called on it to "quit sending in sophisticated equipment that's killing our citizens".
When asked about Bush's warning Ahmadinejad responded: "I didn't receive a message on this matter. We don't have enough time to hear what the others say."
The Iranian leader then went on to mock foreign leaders, including Bush, who arrive in Iraq on unannounced visits.
"When they come to Iraq they come secretly, and their visit lasts only a few hours. We are hiding nothing," he said at a news conference in Baghdad.
He emphasized: "My visit was announced two months ago."
Ahmadinejad's groundbreaking visit to Iraq marks a major step in bolstering ties between Iran and its conflict-torn western neighbour two decades after a devastating eight-year war in the 1980s.