Iranian President Mahmoud Ahmadinejad says talks with the US on Iraq are no longer needed now that a "stable" government is being set up in Baghdad.
Ahmadinejad said it was laughable that Iran wanted nuclear arms
Mr Ahmadinejad told a news conference he hoped the US would "let the Iraqi people govern... and leave them alone".
He also spoke about the international concern over Iran's nuclear programme.
Iran might withdraw from the Nuclear Non-Proliferation Treaty (NPT) if the West tried to prevent it from pursuing nuclear energy, the president warned.
Mr Ahmadinejad said that the Iraqi people could now "stand on their own two feet" and that there was no longer any need for talks between Iran and the US on the issue.
The two countries had earlier agreed to discuss ways to stabilise Iraq.
On Saturday, a four-month deadlock over a national unity government was broken when Shia candidate Jawad al-Maliki was asked to form an Iraqi cabinet.
BBC regional analyst Pam O'Toole says Tehran's top priorities in Iraq are keeping the country united and maintaining a relatively strong Shia-dominated government in power.
On the nuclear issue, Mr Ahmadinejad reaffirmed Iran's right to peaceful atomic energy.
The Iranians insist their nuclear programme is peaceful
He also questioned the benefits of working with the International Atomic Energy Agency (IAEA), which is charged with monitoring the NPT.
"What has more than 30 years of membership in the agency given us?" he asked.
The IAEA has accused Iran of failing to answer all questions about its nuclear programme and reported Tehran to the UN Security Council for non-compliance.
The council has called on Iran to suspend uranium enrichment by 28 April, and the US is trying to rally support for tough action if Iran refuses to do so.
Mr Ahmadinejad dismissed as "laughable" Western concerns that it might be pursuing nuclear weapons and said he did not expect sanctions to be imposed.
"I think even the two or three countries who oppose us are wise enough not to resort to such a big mistake," he said.