Lawmakers are fuming over claims that Capitol Police officers left their service weapons in bathrooms and other spots across the Capitol complex three times this year.

In one instance, a child visiting the Capitol reportedly found a loaded Glock.

"The fact that dangerous weapons were left in the open, potentially within reach of the general public, is unacceptable," said House Administration Committee Chairwoman Candice Miller, R-Mich., and Ranking Member Robert Brady, D-Pa., in a written statement.

Fox News is told lawmakers will have a briefing on the incidents next week.

For Washington's embattled security agencies, it's the latest embarrassing episode. The Capitol Police and other agencies already are under scrutiny over the incident last month where a man breached restricted airspace and landed a gyrocopter next to the Capitol.

The incidents involving misplaced firearms were detailed in a report being reviewed by the Capitol Police Board.

The newspaper Roll Call, which first reported the incidents, said one of the guns -- allegedly left by a member of House Speaker John Boehner's detail in a bathroom in March -- was found by a 7- or 8-year-old child.

Another was found stuffed in a restroom stall in the Capitol Visitor's Center in January. It was discovered by a Capitol worker and belonged to a member of Senate Majority Leader Mitch McConnell's security detail.

Custodial staff located a third weapon two weeks ago at the Capitol Police headquarters.

These firearms are Glocks and do not have conventional "safeties" on them -- they will fire if the trigger is pulled.

The concerns come as congressional officials are closely scrutinizing USCP Chief Kim Dine. Dine offered to resign recently but is staying aboard for now despite lawmakers questioning his oversight of the force.

"We will be looking for a full briefing on these incidents, how they happened, what corrective action has been taken, and how we hopefully do not have similar instances in the future," Miller and Brady said.

Their committee oversees security for the House.

Capitol Police spokeswoman Lt. Kimberly Schneider said the department takes security breaches very seriously. However, she declined to comment on the specific incidents.

"Each disciplinary matter is thoroughly investigated and reviewed, employees are held accountable for their conduct, and they are provided due process in adjudicating these matters," Schneider said in an email. "Depending on the nature and seriousness of the violation, an employee's record, and other required considerations, an appropriate penalty is applied, up to and including termination of employment."

"As a matter of policy," she added, "the department does not routinely discuss internal personnel matters, in order to maintain the integrity of the department."

Fox News' Chad Pergram and The Associated Press contributed to this report.