New Delhi, July 13 -- Ten days before the attempted assassination of Donald Trump in Butler, Pennsylvania, senior Secret Service officials were briefed on a classified threat to the then former President's life-but failed to alert the agents responsible for his protection, a congressional watchdog report has revealed.

The Government Accountability Office (GAO) found that the Secret Service's internal systems for sharing classified intelligence were siloed and ineffective, contributing directly to a breakdown in rally security planning.

"The Secret Service had no process to share classified threat information with partners when the information was not considered an imminent threat to life," the GAO report stated.

The GAO report, release...