WASHINGTON — At least 56 senior officials in the top U.S. aid and development agency were placed on leave Monday amid an investigation into an alleged effort to thwart President Donald Trump’s orders.

A current official and a former official at the U.S. Agency for International Development confirmed the reason given for the move Monday. Both spoke on condition of anonymity for fear of reprisal.

Several hundred contractors based in Washington and elsewhere also were laid off, the officials said.

It follows Trump’s executive order last week that directed a sweeping 90-day pause on most U.S. foreign assistance disbursed through the State Department.

As a result of the freeze, thousands of U.S.-funded humanitarian, development and security programs worldwide had stopped work or were preparing to do so. Without funds to pay staff, aid organizations were laying off hundreds of employees.

An internal USAID notice sent late Monday and obtained by The Associated Press said new acting administrator Jason Gray had identified “several actions within USAID that appear to be designed to circumvent the President’s Executive Orders and the mandate from the American people.”

“As a result, we have placed a number of USAID employees on administrative leave with full pay and benefits until further notice while we complete our analysis of these actions,” Gray wrote.

Trump has signed many executive orders since taking office a week ago, but the notice did not say which orders the employees were suspected of violating.

The senior agency officials put on leave were experienced employees who had served in multiple administrations, including Trump’s, the former USAID official said.

Before those officials were removed from the job Monday, they were scrambling to help U.S.-funded aid organizations cope with the new funding freeze and seek waivers to continue life-saving activities, from getting clean water to war-displaced people in Sudan to continuing to monitor for bird flu globally, the former official said.

Secretary of State Marco Rubio has specifically exempted only emergency food programs and military aid to Israel and Egypt from the freeze on foreign assistance.

The Trump administration and GOP lawmakers, many of them skeptical of the need for foreign aid and eager to see other countries pay more, say they will review each foreign assistance program to determine whether it is directly in U.S. interests and eliminate those that are deemed wasteful or liberal social engineering.

Politico first reported the USAID officials being put on leave.