A meeting between the US and Iran over Iraq appears to be getting closer.
It is hoped diplomatic measures will help to improve security in Iraq
The animosity between the two countries over Iran's nuclear activities has been well documented, but it appears both countries would have much to gain from a stable and secure Iraq.
BBC regional analyst Pam O'Toole examines what the talks would mean for all sides.
What is the significance of the talks between the US and Iran?
If they are held and publicly announced, it would be the first open, direct discussions between Washington and Tehran since shortly after the 1979 Islamic Revolution in Iran - although there were some contacts between the two sides after the fall of the Taleban in Afghanistan in 2001.
Although both sides are insisting that the scope of the talks is very narrow, they would mark a breakthrough in relations.
Could the talks between the US and Iran help stabilise Iraq?
That is open to debate. Given their very different views and the recent rhetoric between them, some say the talks could amount to a dialogue of the deaf, with the two countries trading allegations and lecturing each other, but achieving very little.
It is questionable how much Shia Iran could do to assist in damping down what is essentially a Sunni-led insurgency in Iraq, although it could perhaps offer to tighten its borders to prevent weapons getting through.
It could also offer to try to use its long-standing ties with Iraq's rival Shia parties and groups to try to persuade them to reach agreement on the formation of a new government.
However, even Iraqi Shia parties regarded as close to Iran might be reluctant to be seen to be bowing to Iranian pressure in what is essentially an internal Iraqi issue.
What does Iran hope to gain from the talks?
Recognition of its regional importance, for one thing. It has frequently complained that the United States tries to bully it and does not treat it as an equal partner.
Having the US seek talks because Washington needs Tehran's help over Iraq demonstrates to its own population - and the international community - that Iran is a regional power to be reckoned with.
There are also issues that Iran would like to take up with the United States - for instance, the continuing presence of members of Iran's main armed exiled opposition group, the Mujaheddin-e Khalq, in northern Iraq.
However, the big question is whether Iran - or even the US - might eventually try to broaden the scope of these talks to include Iran's controversial nuclear programme, or other issues which could eventually lead to a deal on the nuclear question.
So far, both insist that the discussions will be limited to Iraq.
Some senior US officials have alleged that Iran's agreement to hold these talks with Washington is an attempt to divert international pressure over its nuclear programme, which is now under consideration by the UN Security Council.
What are Iran's main goals in Iraq?
Some say the Iranian government is secretly pleased that the United States has become bogged down in Iraq, which was to be the centrepiece of Washington's efforts to spread democracy in the Middle East.
Iranian leaders have frequently made speeches alleging that Iraq's problems stem from the presence of American forces there. However, above all else, Iran wants to see Iraq remain united because it fears the possible consequences of fragmentation.
If Iraq were to slide into civil war, that could lead to insurgents slipping over the border and creating instability in Iran. If Iraq broke up and an independent Kurdish state were to emerge in the north of Iraq, that could stir up separatist sentiments in Iran's already restless Kurdistan region.
Tehran has historical links with some of the main Shia parties which dominate the new Iraqi parliament and has a vested interest in keeping a relatively strong, Shia-dominated administration in power there. It wants to see US forces withdraw from Iraq as quickly as possible, but not at the expense of stability.
Iran and Iraq fought an eight-year war in the 1980s. While Tehran clearly does not want Iraq to descend into anarchy, it may quietly hope that it does not become too strong for fear it could pose a threat to Iran in the future.
What influence do Iran's Shia clerics and establishment have in Iraq?
The Iranian government sheltered and supported many Iraqi Shia opposition movements during the time of President Saddam Hussein, including two of the main religious parties, Sciri and Dawa.
Many of these movements continue to have links with Tehran and it still has influence with them.
The radical Iraqi Shia cleric, Moqtada Sadr, recently made an official visit to Tehran. His militia, the Mehdi Army, is influential both in southern Iraq and the Shia suburb of Sadr city in Baghdad. Iraq's most senior Shia cleric, Ayatollah Sistani, was born in Iran.
However, despite their historical links with Tehran, many of these groups and individuals have not always seen eye-to-eye with Iran on a number of issues.
Does Iran want a Shia theocracy in Iraq?
The Iranian establishment might like to see that happen, but they probably also realise that it is not going to.
Even Iraqi parties regarded as being close to Iran disagree with it on the issue of clerical rule.
Ayatollah Sistani does not involve himself directly in politics, although he sometimes offers advice. He has stated his clear opposition to clerics becoming directly involved in politics or standing for office. The ayatollah exercises a powerful influence over Iraqi Shias.
Is there any evidence Iran is helping insurgents?
There have been a lot of allegations, but no firm evidence.
The United States has frequently made general accusations of Iranian interference in Iraq.
Its ambassador in Baghdad, Zalmay Khalilzad, told the Washington Post on 24 March 2006 that Iranian agents were training and arming Shia militias such as the Mehdi Army, which is loyal to Moqtada Sadr, and were also working closely with Sunni Arab-led insurgent forces, including Ansar al-Sunna.
British Prime Minister Tony Blair recently suggested that either Iran, or its ally, Lebanon's Hezbollah, could be the source of sophisticated explosives used in roadside bombs in Iraq.
However, Iran has always denied such allegations and says that Britain and the US have never produced evidence to back them up. Meanwhile, Tehran has accused Britain and the United States of trying to foment trouble in various parts of Iran - something they have also denied.
What business interests does Iran have in Iraq?
Iran has significant business interests in Iraq, although actual figures are difficult to obtain.
There are many traders crossing the border into the largely Kurdish region of northern Iraq and, to a lesser extent, other parts of the country. Tens of thousands of Iranian pilgrims also cross into Iraq each year to visit holy Shia shrines in the south, providing a major source of income for Iraqi people in that region.
If Iraq stabilises in the future, Iran has made it clear that it would like to invest in businesses there, such as car manufacturing.