The militaries of the 30 countries that provide the most soldiers and police officers to United Nations peacekeeping operations also are among those most susceptible to corruption, according to a study released Sunday by an anti-corruption monitoring organization.

The organization, Transparency International, known for its annual corruption rankings of governments around the world, said that in its A-to-F grading for the armed forces of the top troop-contributing countries, only Italy scored higher than a D.

Six of the countries — Burkina Faso, Cameroon, Chad, Egypt, Morocco and Togo — received F grades, Transparency International said.

The three countries that contribute the most troops, Bangladesh, Ethiopia and India — which together provide about 25,200 uniformed personnel, roughly a quarter of the total in United Nations peacekeeping operations — also scored poorly in the study’s rankings. Bangladesh and India each received a D, and Ethiopia an E.