WASHINGTON — State Department officials have accused Secretary of State Rex W. Tillerson of violating federal law by excluding Myanmar, Iraq and Afghanistan from an annual list of countries that use or fund child soldiers, officials said Tuesday.

Mr. Tillerson omitted the three countries from an annual list of offenders, which prohibits them from receiving aid and weapons from the United States, over a unanimous recommendation from internal lawyers and regional bureau heads, according to an internal “dissent” memo first obtained by Reuters.

Excluding the countries from the list makes it easier for the United States to provide military aid. The officials’ unusual use of the State Department’s so-called dissent channel highlights the degree of disapproval regarding the exclusions and the demand for stronger accountability surrounding human rights abuses. The secretary is not obligated to follow any recommendations.

“Beyond contravening U.S. law, this decision risks marring the credibility of a broad range of State Department reports and analyses and has weakened one of the U.S. government’s primary diplomatic tools to deter governmental armed forces and government-supported armed groups from recruiting and using children in combat and support roles around the world,” reads the July 28 memo addressed to Brian Hook, the department’s director of policy planning.