WASHINGTON — Attorney General Eric Holder called Thursday for better record-keeping on how often police officers use force and are themselves attacked, saying the current data is incomplete and inadequate.

With his remarks, Holder joined police union officials, academics and others who have urged collection of more detailed statistical data on officer fatalities and deaths of civilians at the hands of police officers.

“This would represent a common-sense step that would begin to address serious concerns about police officer safety, as well as the need to safeguard civil liberties,” Holder said in a speech at the Justice Department honoring Rev. Martin Luther King.

The FBI publishes data on “justifiable homicides” by police officers and on the number of police officers killed or assaulted, and legislation passed by Congress about 20 years ago directs the Justice Department to keep statistics on excessive force by police. But those figures are widely understood to be incomplete since the reporting by local police departments is voluntary and not all submit their statistics.

The absence of reliable data was brought to the forefront by police-involved deaths last year in New York City and Ferguson, Missouri. Efforts to explore how frequently officers use force were stymied by poor record-keeping and incomplete data. After the killings last month of two police officers in New York by a man who later fatally shot himself, the Fraternal Order of Police led calls for a better accounting of officer fatalities.

Holder said better data are needed on both officer deaths and use of force to provide a more accurate picture of relations between police and the communities they serve.

“It is incumbent upon all of us to protect both the safety of our police officers and the rights and well-being of all of our citizens,” Holder said. “We can, and we must examine new ways to do both.”