Iran's top leaders have forcefully rejected US allegations that Tehran is harbouring terrorists, interfering in Iraq and seeking to develop nuclear weapons.
Khatami said Iraq should choose its own leaders
Supreme Leader Ayatollah Ali Khamenei denounced the United States in a speech to Iran's parliament on Tuesday.
Both President Mohammad Khatami and Foreign Minister Kamal Kharrazi used speeches at a meeting of Islamic states in Tehran on Wednesday to criticise recent statements out of Washington.
Tensions between the US and Iran are high at the moment, derailing a slight warming in relations earlier in the year.
Ayatollah Khamenei was scathing about Washington's description of Iran as part of an "axis of evil".
"We have to do this and that so they will remove us from the axis of evil. What kind of talk is this? Who do they think they are?" he asked.
He urged members of parliament to refuse to give in to US pressure.
Separately, Iran's President Khatami rejected US warnings that Tehran should not to try to build an Islamic republic in Iraq.
Mr Khatami said the "Muslim people of Iraq" had a right to expect "a political regime chosen by the Iraqi people".
Mr Kharrazi, for his part, cautioned Washington against "unilateralism".
Their remarks came after US Defence Secretary, Donald Rumsfeld, on Tuesday warned that Iranian "efforts to remake Iraq in Iran's image will be aggressively put down".
Rumsfeld: Iran being "unhelpful" regarding Iraq
Speaking the same day, White House spokesman Ari Fleischer said the US suspected that weapons development was at the heart of Iran's nuclear industry.
He also called Iran's steps against the al-Qaeda network "insufficient".
Mr Kharrazi rejected the nuclear allegation.
"Any concern over countries' non-compliance with weapons of mass destruction needs to be dealt with through international co-operation," Mr Kharrazi said at the Organisation of the Islamic Conference meeting.
"The resort to force, or directing unverified accusations... will only undermine the current international arrangements," he said.
The International Atomic Energy Agency (IAEA) is due to report on Iran's nuclear programme on 16 June.
Washington hopes the IAEA will turn the heat on Iran by signalling grave doubts that its network of nuclear facilities is merely designed for power generation.
An Iranian foreign ministry spokesman was equally firm in denying US claims that Iran was not taking strong enough measures against al-Qaeda.
"It is the US which is not really serious in fighting terrorism," Hamid Reza Asefi said.
The issue of Iran is said to have revived the split between moderates in the Bush administration who favour diplomacy and hardliners who prefer more robust action.