An internal State Department dispute centers on the recruitment and use of child soldiers in Afghanistan, Burma and Iraq. Here, Afghan boys attend school in Badakhshan province. (Shayaq/Epa-Efe/Rex/Shutterstock/Shayaq/Epa-Efe/Rex/Shutterstock)

The State Department on Tuesday defended Secretary of State Rex Tillerson's removal of three countries from a list of those using child soldiers, after officials upset about his decision wrote a critical dissent memo saying the action violates U.S. law.

The dispute centers on the recruitment and use of child soldiers in Afghanistan, Burma and Iraq. All were included on an original list compiled by senior officials within the State Department and embassies around the world and passed along to Tillerson with the recommendation they be included. Under the Child Soldier Prevention Act of 2008, the State Department must publish a list of offending countries every year, making them ineligible for some types of military aid.

When the annual human-trafficking report came out in June, however, Tillerson had overruled the recommendations, and the original list of 11 nations was whittled down to eight.

His decision prompted a memo filed to the State Department's dissent channel, a vehicle established during the Vietnam War for employees to voice their objections to policies they considered wrong. It was addressed to Brian Hook, the director of policy planning within the State Department, and eventually was shown to Tillerson.

The dissent memo said there was sufficient evidence to include the three countries stripped from the list.

"It is difficult to defend the decision not to list those countries as a legal matter," said the memo, which was first reported by Reuters and has been viewed by The Washington Post.

State Department spokeswoman Heather Nauert said Tuesday that Tillerson based his decision on the "technical" merits of each case.

She said it was in part because the numbers of child soldiers reported in each country were low and unverified and in part because the countries were considered to be making progress in combating the problem.

"No one in the U.S. government likes the use of child soldiers," Nauert said. "It is abhorrent."

Later, Nauert issued a statement saying the eight countries on the list all met the statutory requirement, while Tillerson deemed the other three did not.

"He made this decision after considering the credibility of all the information available to him from multiple sources," she said. "With regard to Iraq, Burma and Afghanistan, the Secretary thoroughly reviewed all the evidence and made a determination about whether the facts justified a listing pursuant to the law."

One of the signatories of the dissent memo on Monday filed a complaint with the State Department inspector general, according to John Tye, who represents the official through his organization, Whistleblower Aid. Tye said the official, who remains anonymous, aims to get Tillerson to amend the human-trafficking report by re-listing the three countries.

"This is not an abstract policy issue," Tye said. "Within weeks of being delisted, the Burmese military began the cleansing of the Rohingya. A lot of the Burmese child soldiers who were cut out of the report within weeks were forced to start ethnic cleansing."

The authors of the dissent memo said the decision to remove Iraq, Afghanistan and Burma weakens U.S. credibility and undermines the State Department's efforts to tackle the issue.

"It has risked sending a message to the authorities in all three countries," the memo said, "that minimal efforts are enough; that we as a government are not interested in upholding international norms, nor in holding countries accountable for ongoing abuses against children; and that we are willing to neglect the legal foundations and principles guiding our advocacy and diplomacy."