One of Iraq's most powerful Shia politicians has condemned the arrest of Iranians by US forces in Iraq as an attack on the country's sovereignty.
The outside of the Iranian liaison office raided by US forces
The comments by Abdel Aziz al-Hakim, made in a BBC interview, are seen as the strongest expression yet of Iraq's concern about the US approach to Iran.
They follow two recent US raids in which Iranians were arrested.
The remarks are interesting as Mr Hakim is seen as close to President Bush, says the BBC's Andrew North in Baghdad.
Mr Hakim also has close links to Iran, after many years in exile there.
Late last year, US troops descended on Mr Hakim's residential compound in Baghdad and detained two Iranian officials.
They were later released, but last week, five more were detained at the Iranian liaison office in Irbil. They are still being held.
US officials say they are linked to the Iranian Revolutionary Guard which they allege trains and arms Iraqi insurgents.
Iran, which has demanded their immediate release, says they are diplomats engaged in legitimate work.
Iraq has sought to bring about a dialogue between the US, Iran and Syria, Mr Hakim, leader of the Supreme Council for the Islamic Revolution in Iraq, told the BBC.
Any tension between Washington and Tehran might have adverse consequences for Iraq, he said.
"Regardless of the Iranian position we consider these actions as incorrect," Mr Hakim said.
"They represent a kind of attack on Iraq's sovereignty and we hope such things are not repeated."
On Sunday, Iraq's Foreign Minister Hoshyar Zebari said that Iraq needed a constructive relationship with Iran.
"We can't change the geographical reality that Iran is our neighbour. This is a delicate balance and we are treading a very thin line.
"We fully respect the views, policies and strategy of the United States, which is the strongest ally to Iraq, but the Iraqi government has national interests of its own," Mr Zebari said. Mr Hakim is said to be close to President George W Bush and has backed his new plan for Iraq.
Speaking after a lengthy meeting with Prime Minister Nouri Maliki, Mr Hakim said that, under the plan, Iraqi security forces would be in charge for the first time in four years, while the multinational troops provide support.
"This came about at the request of the Iraqis. They met and decided to carry out these operations and be fully responsible while the multinational forces support them," said Mr Hakim.