Condoleezza Rice, the US secretary of state, said on Friday she was "quite certain" that direct talks would take place with Iran on the turmoil in Iraq, but did not say exactly when.
"In this narrow set of issues about security in places where we find ourselves in a sense on their border, it is important that we do not have any miscommunication or misinformation," said Rice.
In Tehran on Saturday, Mahmoud Ahmadinejad, the Iranian president, said he supported talks with Washington about Iraq but was suspicious of US motives.
"We essentially do not trust the Americans but we will conditionally negotiate with them about Iraq while taking into account the interests of Iraqis and the world of Islam," Ahmadinejad said, according to the official IRNA news agency.
He did not go into details, but Iranian officials have said the talks would cover only Iraq, not Iran's nuclear programme or other areas of dispute with Washington.
Iran's Supreme Leader Ayatollah Ali Khamenei, who has the last word in all matters of state, has already approved the US-Iranian talks.
Some of the violence in the country is being attributed to neighbouring Iran, and in an interview with the Washington Post, Zalmay Khalilzad, the US ambassador to Iran, accused the Islamic republic of interference in Iraq.
Khalilzad(L) has been authorised
to speak to the Iranians
"Our judgment is that training and supplying, direct or indirect, takes place, and that there is also provision of financial resources to people, to militias," Khalilzad said, adding that Iranian agents were present in the country.
He said he was especially concerned over Iran's links to the Mahdi Army, an armed group loyal to Shia leader Muqtada al-Sadr whom he blamed for the latest rise in sectarian killings in Iraq.
Though Khalilzad has been authorised to speak with the Iranians on the situation in Iraq since last year, the issue returned to prominence with last week's calls by an Iraqi Shia politician to Iran to talk with the United States.
The call prompted anger among other Iraqi politicians who questioned the validity of talks about Iraq that do not involve Iraqis.
Concern in Washington and Baghdad is high over the unabated violence in Iraq, especially in Baghdad and its environs, though officials in both capitals are quick to deny that a civil war is under way.
Donald Rumsfeld, the US defence secretary, added his voice to other US officials expressing their impatience with the length of time taken by Iraqi politicians to decide on a new government.
Talabani (L) is 'optimistic' on the
issue of government formation
"So to the extent that is not happening, obviously, the level of violence continues and people are being killed, and that is unfortunate. And they need to get about the task," Rumsfeld said.
In response to US pressure, Iraqi politicians restarted talks on Friday, a day earlier than planned, after their suspension for a week due to local holidays.
After the restart of talks, Jalal Talabani, the Iraqi president, said he was "optimistic" about the formation of a new government, and said talks had progressed on a wide range of issues, including on the mechanisms of the new government.
His optimism was somewhat undercut by Shia politician Jawad al-Maliki, who at the same press conference said that while talks had occurred over general issues, no discussions on the actual mechanisms had taken place.