This article has been updated.

A federal watchdog on Thursday sent the U.S. Secret Service a formal warning that its overworking of employees is jeopardizing security — citing the discovery that two Secret Service officers were asleep at their posts, according to three government officials familiar with the findings.

The inspector general who oversees the Secret Service issued a management alert, a formal designation that indicates investigators have found a problem so urgent or sweeping that it requires swift attention from senior management.

“This alert describes officer safety issues that may pose an immediate or potential danger to U.S. Secret Service officers and those whom they protect,” the inspector general’s alert says. “We are concerned that the Secret Service’s staffing and scheduling process does not ensure that officers receive adequate breaks while on duty and time off between shifts.”

The management alert stems from a routine check this August of alarms and communication equipment at facilities protected by the Secret Service, the three officials said. In the wake of radio failures when a fence-jumper got inside the White House in September 2014, auditors with the Department of Homeland Security’s Office of Inspector General rode around to various sites with Secret Service staff. They found one officer at an embassy post and another stationed at the White House complex who appeared to be asleep while on duty.

From a White House intruder to exploits with Colombian prostitutes, here’s a look at various scandals that have rocked the Secret Service. (Gillian Brockell and Jackie Kucinich/The Washington Post)

Secret Service leaders strenuously objected Thursday to Inspector General John Roth’s conclusions that these incidents show a broader problem in the agency’s work schedules. A Secret Service spokesman said the evidence shows an overtaxing work schedule was not the reason for the two employees’ lack of alertness. In one case, the officer told investigators that cold medicine he took that day had made him drowsy, two government officials said. The other officer ostensibly had a very full work schedule on paper, but a large chunk of that was sitting and sleeping while flying back in a military transport plane from President Obama’s trip to Kenya.

The IG said that one officer had worked 60 hours of overtime in the previous pay period before falling asleep. But Service officials said that was misleading, as he only worked 24 hours of overtime in the two weeks prior and had five days off during that time.

“The Secret Service does not agree with the OIG’s conclusion that these officers’ misconduct was due to fatigue caused by staffing and scheduling issues,” a Secret Service spokesman said. “We provided the OIG with factual corrections to their draft report.  With these errors corrected, we fail to understand how the OIG could logically arrive at the same conclusion.”

The Secret Service also questioned the reason for the management alert, as Service staff were with the auditors when the officers were found sleeping and took immediate action to report them and recommend discipline for them both.

“ We were present with the OIG team during their observations of both incidents, and view these matters as entirely within the purview of the Secret Service,” the spokesman said. “This matter is behind us and disciplinary action is well in process.  The Management Alert offers neither new information nor value to the Secret Service and should not warrant the ongoing attention of the OIG.”

Overscheduling has plagued the Secret Service in the recent past, especially the Secret Service’s Uniform Division officers, who provide security at the White House and the vice president’s residence at the Naval Observatory. In the wake of the embarrassing fence-jumper incident, many officers complained bitterly about how often they are forced to work on their days off due to staffing shortages. An administration-appointed panel recommended increasing the Service’s staff by 85 agents and 200 officers to properly handle its workload and security postings.

New Secret Service Director Joseph Clancy has pledged that improving staffing, with Congress’s help, was his first priority in taking the job permanently in February.

Roth’s last management alert to the Service was sent in April and concerned failing security systems at the residences of former presidents, who are also protected by the Secret Service.

“These notifications are used by the OIG to inform senior DHS managers of conditions which pose an immediate and serious threat of waste, fraud and abuse in agency programs,” the inspector general’s Web site reads. “These alerts, usually triggered by findings made in the course of our audit, inspections and investigative work, may also contain recommendations to correct the identified concerns.”