Seven more US soldiers were killed in separate attacks around Iraq on Saturday, the military said, as American casualties remained high after two of the mission's bloodiest months since the war began.

By recent Iraqi standards the bloodshed was not extreme, but the diverse motivations of the combatants underlined the complexity of the overlapping conflicts ravaging Iraq and undermining the US mission.

The latest fighting erupted after a former commander of American forces in Iraq, retired army Lieutenant General Ricardo Sanchez, said the United States could no longer win the war and must find a way to stave off defeat.

“I am absolutely convinced that America has a crisis in leadership at this time," Sanchez told AFP in an interview given in Texas.

"I think if we do the right things politically and economically with the right Iraqi leadership we could still salvage at least a stalemate, if you will -- not a stalemate but at least stave off defeat," he said.

Sanchez retired last year and is the highest-ranking former military leader yet to suggest the Bush administration fell short in Iraq. He commanded troops there between June 2003 and June 2004.

The general was speaking out amid a bitter debate in the United States over the future of their military commitment in Iraq, where more than 140,000 GIs are battling to quell sectarian violence and defeat a violent insurgency.

Their current commander, General David Petraeus, hopes this year's so-called surge in US troop numbers will eventually tamp down the violence enough to allow Prime Minister Nuri al-Maliki to kick-start a political peace process.

But the week's violence demonstrates the bewildering variety of armed factions, fighting in several local wars, that will confront any would-be peacemaker if he were decide to engage with them.