Bush said on Thursday that helping Iranians after last week's devastating earthquake was the right thing to do, but that US aid did not signal a thaw in relations with Tehran.
"What we're doing in Iran is we're showing the Iranian people the American people care, that they've got great compassion for human suffering," he told reporters after hunting quail in Farfullias, Texas, with his father.
But if Tehran wants better relations, it must turn over any member of Usama bin Ladin's al-Qaida network it has in custody, abandon efforts to develop unconventional weapons, and embrace political reforms.
"The Iranian government must listen to the voices of those who long for freedom, must turn over al-Qaida that are in their custody and must abandon their nuclear weapons program," he said.
Earlier in the day Iranian officials had hinted that US aid to earthquake victims may have eased decades of mistrust between the two arch-foes.
During a memorial service at Bam's Friday Mosque the country's former President Akbar Hashemi Rafsanjani said recent developments could have an impact on the hostile relations between Washington and Tehran.
"I'm not sure but the signs indicate that," the official IRNA news agency reported him as saying on Thursday.
President Muhammad Khatami's brother went further, implying the US response to the earthquake might win an unspecified reciprocal gesture from Iran.
"We're evaluating the American government's positive behaviour and I'm sure that goodwill will be answered with goodwill," Muhammad Reza Khatami, deputy parliament speaker and Khatami's younger brother, said.
Khatami says US-Iran relations
will not be altered by the aid
However, earlier this week the president himself said US-Iranian problems were rooted in history and would not be altered by the US aid.
Washington broke ties with Iran shortly after the 1979 Islamic revolution and dubs it part of the "axis of evil".
But it has sent scores of relief workers to Bam and tonnes of aid to Iran.
It has also temporarily eased some sanctions on the Islamic Republic to speed the delivery of humanitarian relief, and hinted at a willingness to resume some dialogue with Tehran.
Meanwhile, two miraculous rescues pierced the gloom in the devastated city of Bam on Thursday
Relief workers pulled a young man and a child alive from the ruins six days after the quake flattened the medieval town 1000km southeast of Tehran.
"At least we've saved one life. I have been in war and through many struggles and I've never been so happy," Red Crescent worker Ali Ashghar Namdari said after a dazed and mumbling shopkeeper was discovered under a wardrobe.
Bush has labelled Iran as being
part of the ' axis of evil'
Relief workers in Bam said shopkeeper Yadollah Saadat was found alongside the corpses of six dead relatives.
"They thought he was dead and then they realised he was alive," his wife, Fatimeh Asghari, 22, said as she sat next to Saadat being examined by medics. "I can't express how happy I am."
And Iran state radio said a nine-year-old girl covered with dust and dirt had also been rescued from the rubble of her family's flattened house. She was described as in fragile condition.
Government officials have said the final death toll from the quake, measuring 6.8 on the Richter scale, may reach 50,000, making it one of the worst natural disasters of recent decades.