Arch enemies the United States and Iran launched a second round of rare face-to-face talks in Baghdad on Tuesday aimed at stemming the raging violence in Iraq.

The talks began at 10.15 am (0615 GMT) at the office of Prime Minister Nuri al-Maliki, who began the meeting with a brief speech, according to an official at the Iraqi premier's office.

Photographs from the meeting showed the three delegations sitting around a triangular arrangement of tables in conference room in Maliki's offices inside Baghdad's heavily-fortified Green Zone.

The US was represented by its ambassador in Baghdad, Ryan Crocker, while Tehran's envoy Hassan Kazemi Qomi headed the Iranian delegation in the talks attended by Iraqi officials.

As with a similar meeting held on May 28, officials said the talks would only focus on the security situation in Iraq, leaving aside a roster of other disputes between the United States and the Islamic republic.

May's meeting did not achieve any major breakthrough as both sides stuck to their familiar positions, with Tehran calling for a US withdrawal and Washington accusing Iran of fomenting violence.

The United States broke off relations with Iran in 1980, when Islamic revolutionaries seized the US embassy in Tehran and held its diplomats hostage for 444 days.

The two countries remain at loggerheads over a range of issues including Iran's nuclear programme, which the United States claims is aimed at producing nuclear weapons, an accusation vehemently denied by Tehran.

US forces also accuse Iran of arming and training Iraqi militias, allegations firmly denied by Tehran.

Relations have also been chilled by the detention in Iraq by US forces of at least five Iranian officials whom Tehran insists are diplomats, but Washington says are covert operatives from of Iran's elite Revolutionary Guard.

Tehran in turn has detained four US-Iranians accused of espionage and harming national security by being linked to alleged US efforts to topple Iran's clerical authorities.

On Monday, US State Department spokesman Sean McCormack ruled out raising the issue of the US-Iranians at the talks, saying their "primary focus is on Iraq security."

Tehran claimed that scholars Haleh Esfandiari and Kian Tajbakhsh, who were arrested in May, had exposed in television statements a US plot to overthrow Iran's Islamic authorities through a peaceful "soft revolution."

California-based businessman Ali Shakeri has also been detained. Parnaz Azima, a journalist for Radio Free Europe's Persian arm, is technically at liberty but has had her passport confiscated and cannot leave the country.

Asked whether Washington would miss a rare opportunity by not raising the fate of the four, McCormack said, "I think it is a missed opportunity for the Iranians not to allow these people to leave over the past two months."

Given the acrimonious backdrop, Iraqi lawmakers were divided in their expectations of Tuesday's meeting.

"Nothing much is expected from the US-Iran meeting," said lawmaker Mahmud Othman, a Kurd. "The US wants Iran to keep off Iraq and Iran wants US to leave Iraq. Each side has its own agenda," he said.

"Iraqis are insisting on such meetings because they themselves have failed to solve the problem. But Iraq's problems can be solved only by the Iraqis. They should work together."

But for Iraq's Shiite leaders, known for their close links with Shiite Iran, the meeting was a positive step.

"There is a strong will by the three parties to solve the problems and support the Iraqi government," said Humam Hammoudi, MP from the Shiite Supreme Iraqi Islamic Council, a party known to be close to Iran.

Shiite MP Abbas al-Bayati said May's meeting had broken the "psychological barrier and the upcoming meeting will put in place a practical framework to help the three parties support the (Iraqi) political process."

PHOTO CAPTION

Iraq's Prime Minister Nuri al-Maliki (far end of table) presides over a May 2007 meeting between U.S. and Iranian officials in Baghdad. (Reuters)