By Margaret Chadbourn

WASHINGTON (Reuters) - Former U.S. President George W. Bush on Sunday promoted a new initiative to help veterans transition back to civilian life and aid in the treatment of post-traumatic stress disorder.

The onetime commander-in-chief, who led the United States into war in Afghanistan in 2001 and Iraq in 2003, said he wants to highlight the challenges facing service members returning from war zones, as well as their families.

"I have a duty," Bush said in an interview that aired on Sunday on ABC's "This Week."

"Obviously I get slightly emotional talking about our vets because I have an emotional...," Bush said, trailing off.

"I'm in there with them," he added.

About 2.5 million U.S. service members have served in Iraq and Afghanistan since 2001, according to the Department of Defense. Troops have since left Iraq and are expected to wind down their involvement in Afghanistan within the year.

More than 50,000 U.S. and coalition service members have been wounded in more than a decade of war.

The Dallas-based Bush Institute, a public policy center founded in 2009 by the former president and his wife Laura, is working with a coalition of government, nonprofits, private companies and universities on the initiative, which also target ways to encourage employers to recruit and retain veterans.

"We've got a problem, too many vets are unemployed," said Bush in one of his few public appearances since leaving the White House. "There's what we call a military-civilian divide."

The unemployment rate for recent veterans remains high, at around 10 percent as of the end of 2013 compared to just above 7 percent for nonveterans.

The Bush Institute also plans to tackle PTSD, a condition thought to affect more than 270,000 veterans of the Iraq and Afghanistan wars. The Veterans Affairs Department has awarded disability benefits to more than 150,000 PTSD patients.

PTSD develops after a terrifying ordeal that involves physical harm or the threat of it, according to the National Institute of Mental Health.

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Bush Institute researchers expect to release materials this spring on a study of the post-9/11 veteran population, including suggestions on ways to best treat and help erase the stigma often associated with the condition.

White House officials have pushed awareness efforts for veterans, military personnel and their families through the Joining Forces campaign, founded by Jill Biden, wife of Vice President Joe Biden, and first lady Michelle Obama.

(Reporting by Margaret Chadbourn; editing by Ros Krasny and Amanda Kwan)