Syrian Foreign Minister Walid al-Moualem, making the first visit by a Syrian minister to Iraq since the US-led invasion in 2003, signed an accord with Iraqi counterpart Hoshiyar Zebari in which they agreed US troops should stay in Iraq for now.

Moualem had earlier called for the setting of a timetable for the withdrawal of 140,000 US troops. The document said troops should gradually withdraw once they were not needed.

US National Security Council spokesman Gordon Johndroe called on Syria to demonstrate its commitment to helping the Iraqi government. "One of the first steps Syria could take is to strengthen its border with Iraq and stop the flow of foreign fighters into that country," he said in a statement.

In an apparent bid to counter US influence in the region, Iranian President Mahmoud Ahmadinejad invited his Iraqi and Syrian counterparts to a weekend summit in Tehran to tackle the chaos in Iraq, Iraqi lawmakers said Monday.

The diplomatic gambit coincided with a groundbreaking visit to Baghdad by Syrian Foreign Minister Walid Moallem, who was challenged over Damascus' role in supporting the Sunni insurgency.

The Iraqi government said diplomatic relations between the two countries severed nearly a quarter-century ago would be restored by Tuesday.

How far either foreign government can limit mounting sectarian violence in Iraq is unclear, as hundreds of deaths a week fuel fear and hatred at the heart of Iraqi society.