Ryan Crocker, the new American ambassador to Iraq, was sworn in at the U.S. embassy in Baghdad's heavily fortified Green Zone on Thursday.
During his first comments as the new ambassador, Crocker reaffirmed US support for the Maliki-led government, saying, "We must stand by the Maliki government and all Iraqis who seek a better future and remain committed to their success.
But Crocker also voiced a reminder that the Iraqis have much progress to make: "This government, under the leadership of Prime Minister Maliki, must continue to take the necessary steps to unify this country, and to deliver tangible improvements to the lives of all Iraqis."
Crocker said the US faces "historic challenges" in Iraq that "will demand a strong commitment and broad performance from the Iraqi government and the international community."
Even so, Crocker emphasized that "all of these (challenges) will be very hard, but if I thought it was impossible I would not be standing here today."
Lt. Gen. Petraeus attended the swearing-in ceremony, held at the embassy inside the Green Zone in what was formerly Saddam's Republican Palace.
President Bush nominated Crocker in December to replace outgoing Ambassador Zalmay Khalilzad, who is now slated to represent the US at the UN.