Vice President Joe BidenJoseph (Joe) Robinette BidenThe Hill's 12:30 Report Pence talks regularly to Biden, Cheney: report Biden moving toward 2020 presidential run: report MORE choked up Thursday while thanking U.S. troops in Iraq, telling them that the mission there has changed.

Biden, who is in Iraq after visiting Afghanistan and Pakistan earlier in the week, hailed the sacrifices of the troops, becoming emotional when he described meeting with wounded soldiers.

"The thing that amazes me about you all is no matter where I go in these hospitals" and ask what the troops need, Biden said, the reply "almost without exception is: 'Mr. Vice President, can you get me back to my unit?' "

The vice president told the troops that the transition away from combat to support is well under way.

"The fact of the matter is there is a lot that is changing," Biden said. "There is transition. Our mission has now fundamentally shifted."

Biden said the Iraqis are "on the verge of creating a country that will be democratic, sustainable and, God willing, prosperous."