Foreign Minister Manouchehr Mottaki said Tehran would be willing to consider talking to Washington, its arch-foe for almost three decades, at the level of deputy foreign minister.

"The talks between Iran and the United States over Iraq at the level of deputy foreign minister can be studied," Mottaki said after a cabinet meeting, the state-run IRNA agency reported.

"If America makes an official request in this regard it can be examined," he added.

US Ambassador to Iraq Ryan Crocker and Tehran's envoy Hassan Kazemi Qomi held a second round of talks on Tuesday in Baghdad over security in Iraq to follow up a first meeting on May 28.

The outcome of the meeting appeared to be very mixed with both sides still at loggerheads over who was to blame for the daily violence in Iraq.

The United States accused Iran at the meeting of stepping up its alleged support of militia groups and Crocker admitted afterwards the encounter had been marked by "heated exchanges".

"We've got a lot of problems with the Iranians and, you know, face to face we're not going to pull any punches," he told Washington-based reporters in a conference call afterwards.

Iraqi officials hailed what they said was the creation of a tripartite security committee. However, US officials were more downbeat, saying Washington would "take a look" at the idea.

Mottaki did not say which diplomats could be involved in any higher-level talks.

Iran has several deputy foreign ministers, the highest ranking being Mehdi Mostafavi. The US deputy Secretary of State is former US ambassador to Iraq John Negroponte.

The first round of talks between Crocker and Kazemi Qomi were the highest-level public talks between the two sides in almost three decades. A meeting between deputy foreign ministers would be seen as a significant breakthrough.