WASHINGTON - President Bush's choice to head the military Joint Chiefs of Staff said Tuesday an increase of troops in Iraq is giving commanders the forces needed to improve security there.

"Security is better, not great, but better," said Navy Adm. Michael Mullen, speaking before the Senate Armed Services committee at his nomination hearing.

However, Mullen acknowledged under questioning that, "there does not appear to be much political progress" in Iraq.

"I believe security is critical to providing the government of Iraq the breathing space it needs to work toward political national reconciliation and economic growth, which are themselves critical to a stable Iraq," Mullen said. "Barring that, no amount of troops and no amount of time will make much of a difference."

He said morale is still high, but he doesn't take for granted the service of U.S. troops. He said the war has spread forces thin.

"I worry about the toll this pace of operations is taking on them, our equipment and on our ability to respond to other crises and contingencies," he said.