Baghdad, Iraq ? The U.S. ambassador to Iraq warned Friday that time is running out for Prime Minister Nouri al-Maliki to contain the burgeoning sectarian bloodshed that threatens to plunge the country into civil war.

“He has a window of a couple months,” said the ambassador, Zalmay Khalilzad. “If the perception is that this unity government is not able to deal with this issue, then a big opportunity would have been lost and it would take a long time to address this issue.”

His remarks, which came during a surge in reprisal killings in Baghdad, reinforced comments by several senior U.S. military officials this week that al-Maliki’s government must move urgently to tackle the militias and death squads wreaking havoc across the country.

Unlike the military commanders, however, Khalilzad said he and President Bush still had full confidence in al-Maliki and were “cautiously optimistic” that his government had the political will to rein in the bloodletting.