Iran has invited Syrian President Bashar al-Assad for talks in Tehran, and he could join a summit between the Iranian and Iraqi presidents, officials said today.
Iraqi President Jalal Talabani is due to visit Tehran at the weekend for a long-planned bilateral summit with Iranian President Mahmoud Ahmadinejad.
That meeting comes amid increased talk of diplomatic efforts to involve Iraq's neighbours Syria and Iran in helping to curb violence in Iraq and prevent a plunge into civil war.
In Baghdad, a Iraqi government source said Mr Assad might join the Iraqi-Iranian talks in Tehran but that nothing was certain and, with the involvement of the United States in the process, last-minute changes of plan were possible.
A Syrian official said there were no plans for a tripartite summit.
In Washington, a US State Department spokesman voiced scepticism that any meeting between Iran, Syria and Iraq could help to reduce the violence and said similar meetings in the past had not resulted in that happening.
United Nations Secretary General Kofi Annan urged Iran and Syria to be "part of the solution" in Iraq and help the Baghdad government end sectarian fighting. Mr Annan said he had spoken with both the Syrian and Iranian presidents in recent days to prod them to help ease the conflict in Iraq.
Iraq and Syria agreed today to restore full diplomatic relations in an accord in which Syria accepted that US troops should stay in Iraq while the Iraqi government needed them.
Washington, struggling to control violence in Iraq, sees both Iran and Syria as sources of instability in the country.
Syrian Foreign Minister Walid al-Moualem, making the first visit by a Syrian minister to Iraq since the US-led invasion in 2003, signed the agreement with his Iraqi counterpart Hoshiyar Zebari this morning.
Iraq hopes the move may help stem what it says is Syrian support for militants.
The two governments agreed to restore full diplomatic ties, reopening their embassies in Damascus and Baghdad. An agreement in principle was struck some months ago. Ambassadors would be named and embassies opened shortly.
Iraq and Syria severed ties when Syria sided with Iran during the 1980-1988 Iran-Iraq war.
US and Iraqi officials have long accused Damascus of doing too little to stem the flow of foreign Islamist fighters and weapons across its long, porous border. The US military said yesterday that between 70 and 100 foreign fighters were still crossing the border each month.
Syria says sealing the border is impossible and Iraq must do more to patrol its side.