By Jonathan Marcus
BBC diplomatic correspondent
The indications in both Tehran and Washington are that direct talks between the US and Iran on Iraq could be in prospect.
Rising violence in Iraq is making both the old rivals worried
But what does this potential dialogue indicate?
Iraq has always been an important element in the complex diplomatic dance linking the US and Iran.
Name almost any sphere - proliferation, energy, security or the war on terror - and Iran and the United States are firmly on opposite sides.
But on Iraq, while their fundamental interests differ, the worsening situation on the ground means that they may have some short-term goals in common.
Indeed, the idea of some kind of Iran-US dialogue on Iraq was suggested last November by the US ambassador in Baghdad, Zalmay Khalilzad.
The idea hung in the air, but nothing materialised.
Now, though, circumstances are different. For one thing the increasing violence and disorder in Iraq is making Tehran just as worried as Washington.
Iranian investment in Iraq is significant. Tehran has nurtured close ties with Iraq's Shia majority and the main Shia political parties who now dominate the new Iraqi parliament.
The last thing the Iranians need or want is wholesale instability there.
The US view has also shifted. It has become more pragmatic, if you like.
There is a growing realisation that Iran has legitimate concerns about what goes on in Iraq.
The view in Washington, though, remains ambivalent. Many, including President George W Bush, see Iran as actively working to destabilise Iraq.
And then there is the wider picture, with the Bush administration's new National Security Strategy stating bluntly that the US "faces no greater challenge from a single country than from Iran".
Indeed, proliferation concerns and the long-running dispute over Tehran's nuclear ambitions may well trump whatever limited understandings there may be on Iraq - assuming, that is, that the talks do actually go ahead.