The Secret Service can't afford to pay more than 1,000 agents needed to protect President Trump and his family, as the agency has reached its budgetary limits in part due to the size of President Trump's family and its frequent travel.

In an interview with USA Today, Secret Service Director Randolph "Tex" Alles said more than 1,000 agents, about one-third of the Secret Service workforce, have hit the salary caps and overtime allowances mandated under the federal law that were supposed to last the full fiscal year.

Unless Congress steps in to raise the caps, the agency said more than 1,100 agents will be ineligible for additional overtime pay.

"We have them working all night long; we're sending them on the road all the time," Alles told USA Today. "There are no quick fixes, but over the long term, I've got to give them a better balance here."

The heightened workload for the Secret Service is due in part to the sheer number of Trump's family members that require protection, as well as the president and his family's frequent travel. Under the Trump administration, 42 people have Secret Service protection, including 18 family members. The Obama administration had 31 protectees.

"The president has a large family, and our responsibility is required in law," Alles said. "I can't change that. I have no flexibility."

Due to the workload and constant travel, there has been an exodus from the Secret Service's ranks, according to USA Today, but Alles has started discussions with members of Congress to raise the combined salary and overtime cap from agents in response to the crunch.

The combined cap is currently $160,000, and lawmakers are discussing raising it to $187,000 for the rest of Trump's first term.

But even if the cap were lifted, the Secret Service said about 130 agents wouldn't be compensated for the hours already logged.

Though the agency hoped its workload would normalize after Trump's inauguration, the president has traveled nearly every weekend to one of his properties, adding to the strain.

Since assuming the presidency, Trump has taken seven trips to Mar-a-Lago, Fla., traveled five times to his golf club in Bedminster, N.J., and visited Trump Tower in New York City once.

Each trip to Mar-a-Lago costs at least $3 million, according to an estimate from the General Accounting Office, and the Secret Service has already spent $60,000 on golf cart rentals so far this year at Trump's Florida and New Jersey properties.

In addition to traveling with the president to his East Coast properties, Secret Service agents have also traveled with Donald Trump Jr. and Eric Trump, who require details, for various business trips.

Secret Service spent nearly $100,000 for hotel rooms in Uruguay, where Eric Trump traveled for business, for example.

Alles said he discussed the agency's issues with the White House.

"They understand," he said. "They accommodate to the degree they can and to the degree that it can be controlled. They have been supportive the whole time."

The Secret Service director, whom Trump tapped to take over the agency in May, said he expects additional hiring efforts to take the pressure off the agency.

The Secret Service hopes to increase its force of 6,800 to 7,600 by 2019, and 9,500 by 2025.