Baghdad: Prime Minister Nouri Al Maliki told lawmakers Monday that Iraqi forces were not ready to take over security from the US military across the country.

Al Maliki, a Shiite Islamist, defended his government in the face of blistering criticism from both Iraqi and US lawmakers. Some Democratic legislators in the United States have even called for him to be replaced.

"There have been tangible improvements in security in the recent period in Baghdad and the provinces but it is not enough," he told parliament.

"Despite the security improvement, we still need more efforts and time in order for our armed forces to be able to take over security in all Iraqi provinces from the multinational forces that helped us in a great way in fighting terrorism and outlaws."

"We succeeded in stopping Iraq from sliding toward civil war, which was threatening our beloved country," Maliki said.

Al Maliki also pledged his commitment to reconciling the country's majority Shiite and Sunni Arabs.

His comments came hours before the US ambassador to Iraq, Ryan Crocker, and top US commander General David Petraeus were to appear before Congress to deliver reports on Iraq's progress amid a debate over calls to start bringing American troops home.

The two Americans were widely expected to maintain that this year's troop buildup has reduced violent attacks in Baghdad and argue for more time to restore security.

Al Maliki said that violence had dropped 75 per cent in the Baghdad area since the US began pouring in additional troops at the start of the year. He gave no figures.

"The key to reconstruction, economic development and improving peoples' standard of living is security," he said.