Japan and the United States are set to change a bilateral rule to conditionally let civilians who are employed by U.S. military bases in Japan face trial over accidents and crimes that occur while they are on duty, sources close to the matter said Sunday.

The change is aimed at fixing what one of the sources described as "a legal loophole" in the Status of Forces Agreement, or SOFA.

The rule in question is so vague about how nonmilitary U.S. staffers are to be treated after accidents and crimes that neither Japanese nor U.S. authorities can try them.

Both countries will formally agree on the matter at a meeting of the Joint Committee, the sources said. SOFA governs the operations of the U.S. military in Japan.

SOFA stipulates that the U.S. has primary authority to try both military and nonmilitary U.S. personnel suspected of crimes while on duty, whereas Japan can try them if they are off duty.

The sources said the two will agree the U.S. has primary authority to try nonmilitary U.S. staffers, but that Japan will be able to do so as well as an exceptional measure when it is determined a trial in the U.S. would be difficult.

The Japanese and U.S. governments are also reviewing another rule to allow Japanese prosecutors indict both service members and nonmilitary staffers at U.S. bases in Japan if they are involved in traffic accidents after drinking alcohol at official events.