WASHINGTON - US President Barack Obama will take his Iran pitch to a gathering of 12,000 veterans Tuesday and argue progress is being made in righting "systemic" problems in health services for the military.

Obama is traveling to Pittsburgh, Pennsylvania to address a convention of the Veterans of Foreign Wars group, which boasts 1.9 million members.

In addition to announcing measures designed to curb predatory lending targeting the military, Obama "will be speaking about our foreign policy, including Iran," said White House advisor Jeff Zients.

Obama has framed the recent nuclear deal as a choice between diplomacy and war.

While campaigning for the presidency in 2008, Obama told a battle-weary nation he would end the long and bloody conflicts in Iraq and Afghanistan.

Now he will be hoping that those who know war best are receptive to the case that another war, this time with Iran, should be avoided at all costs.

Obama is also expected to address the recent killing of five US troops in Chattanooga, Tennessee.

Four US marines and a sailor were killed after 24-year-old Mohammad Youssuf Abdulazeez opened fire on two military centers.

Obama is also expected to tackle a multi-year crisis in the Department of Veterans Affairs.

An inspector general report a year ago found "systemic" problems in health care for former combatants, with up to 40 veterans dying while waiting for treatment in Phoenix alone.(AFP)