Baghdad ? In mounting bloodshed south of Baghdad, suspected Shiite Muslim militiamen stormed into a Sunni Arab home Tuesday and gunned down seven family members, including a baby being bounced on her mother’s shoulder.

Shadowed by the violence, U.S. Ambassador Ryan Crocker, co-author of a highly anticipated report to Congress next month, said Washington’s blueprint for reconciliation was insufficient to win back control of Iraq. Congressional benchmarks such as laws to share oil revenue and reform security services don’t tell the whole story, he said.

Crocker and the U.S. military commander, Gen. David Petraeus, may be heading into a storm of discontent as they argue before Congress that American troops need more time in Iraq.

The gruesome family murder south of the capital Tuesday underlined unabated sectarian violence. Even President Bush acknowledged frustration with Iraqi Prime Minister Nouri al-Maliki’s leadership during a Tuesday trip to Canada.