The Bush administration's nominee to be ambassador to the United Nations, Zalmay Khalilzad, moved closer to confirmation on Wednesday as the Senate Foreign Relations Committee voted its approval.

Khalilzad, who this week left a posting as U.S. ambassador to Iraq, was approved by the committee for the U.N. envoy job on a unanimous voice vote. That sent his nomination to the Senate floor, where confirmation is expected soon.

Khalilzad's nomination has so far been without controversy despite criticism by many in the Democratic-run Congress of the White House's Iraq policy.

At a hearing earlier this month, the nominee received praise from senators impressed by his handling of the difficult Baghdad posting, which he had held since June 2005, and his performance as U.S. ambassador to Afghanistan before that.

As the chief U.S. diplomat at the United Nations, Khalilzad would replace John Bolton, who was criticized for being abrasive and never won Senate confirmation. Bush had ignored lawmakers' objections to give Bolton a temporary appointment but it expired earlier this year.

Khalilzad, 61, who was born in Afghanistan, says reform of the United Nations is "imperative" but also thinks the United States should pay its dues to the organization in full and on time. Since the 1980s, the United States has been paying its U.N. contributions nearly a year late.

In contrast with Bolton, who resisted diplomatic overtures to countries the administration considered adversaries like Iran or Syria, Khalilzad says he has an "openness to engage" with countries whose behavior the United States would like to see change.

He recently met Syrian and Iranian officials to discuss the involvement of border countries in solving Iraq's problems. At his last press conference in Baghdad this week, he also said U.S. and Iraqi officials were in contact with some Sunni Arab insurgent groups in Iraq to try and build an alliance against al Qaeda there.

Khalilzad has promised to make the Darfur crisis a priority if he is confirmed in the U.N. job.

He is being replaced in Baghdad by Ryan Crocker, a career diplomat who most recently served as U.S. ambassador to Pakistan.