Official figures showed that close to 700 civilians and members of the security forces were killed in a sharp escalation of attacks in May, one of the deadliest month's since the US-led invasion of Iraq in March 2003.

Unveiling his government programme, Prime Minister Ibrahim Jaafari pledged Tuesday to boost security as Iraqi forces conducted a massive anti-insurgency operation in the capital.

With Iraqi officials conceding that their forces are not yet ready to take over security, the UN Security Council on Tuesday extended the mandate of multinational forces as requested by Baghdad, "until the completion of the political process."

The council said in a statement it "welcomed the progress made in recruiting, training and equipping Iraqi security forces and look forward to those forces progressively playing a greater role and ultimately assuming responsibility for Iraq's national security."

Following the UN decision, Iraq Foreign Minister Hoshyar Zebari addressed the council, hitting out at Syria's alleged involvement in the insurgency.

"We have learned recently that Syria has stopped more than a thousand foreign fighters from entering Iraq from Syria. We welcome this action but note that it confirms our long-held view that Syria has been one of the main transit routes for foreign terrorists," Zebari said.

Syrian Defence Minister Hassan Turkmani dismissed the claims as "false accusations instigated by enemies."

Washington and Baghdad have long accused Damascus of not doing enough to prevent what they say is the flow of insurgent fighters across the border.

In Iraq, a suicide car bomber targeted the main civilian entrance to Baghdad's airport, wounding 15, as Iraqi forces fanned out through the city in the largest domestic security push since the US-led invasion.

"The car driven by a suicide bomber exploded near checkpoint number one," through which most civilians and security contractors pass to enter or leave Iraq, an interior ministry source said.