()  The future of the U.S. Agency for International Development (USAID) is uncertain amid changes under the Trump administration and a freeze imposed on billions of dollars in foreign assistance.

A week after President Donald Trump ordered a 90-day pause on foreign aid, two top USAID security officials were removed after refusing to grant representatives of Elon Musk’s Department of Government Efficiency access to restricted areas, the Washington Post reported Sunday.

Congressional Democrats have challenged the administration, fearing Trump may dissolve USAID’s independence and merge the agency with the State Department.

Here’s a closer look at USAID and its mission:

What is USAID?

USAID provides humanitarian assistance to other countries impacted by conflicts and assists developing countries, primarily by dishing out funds to nongovernmental organizations, foreign governments and international organizations, or other U.S. agencies, according to the Congressional Research Service (CRS).

The agency has a budget of over $50 billion.

President John F. Kennedy created the organization at the height of the Cold War to counter Soviet influence. USAID today is at the center of U.S. challenges to the growing influence of China, which has a successful “Belt and Road” foreign aid program of its own.

Congress passed the Foreign Assistance Act in 1961, and Kennedy signed that law and an executive order establishing USAID as an independent agency.

The U.S. is by far the world’s largest donor of humanitarian aid, with USAID administering billions of dollars in humanitarian, development and security assistance in more than 100 countries.

Why do some want USAID dismantled?

USAID, whose website vanished Saturday without explanation, has been one of the federal agencies most targeted by the Trump administration in an escalating crackdown on the federal government and many of its programs.

Several federal websites have also gone dark in recent days.

The Trump administration and Secretary of State Marco Rubio have imposed an unprecedented freeze on foreign assistance that has shut down much of USAID’s humanitarian, development and security programs worldwide compelling thousands of layoffs by aid organizations and ordered furloughs and leaves that have gutted the agency’s leadership and staff in Washington.

Tech billionaire Elon Musk said on X that he believes USAID is a “criminal organization” that should “die.”

Musk was responding to the news that senior officials at USAID physically attempted to block people from Musk’s new department from having access to secure systems, NBC News reported.

The Trump administration is making USAID a target in its wide changes to the federal government. In a three-page letter last week, it was revealed Trump is considering merging the agency into a branch under the State Department.

Democrats have slammed Trump over the reports about the merger, noting the agency is “by statute, an independent establishment.”

How are lawmakers reacting?

Republicans and Democrats have long fought over the agency, arguing whether humanitarian and development aid protects the U.S. by helping stabilize partner countries and economies or is a waste of money.

Democrats argue Trump has no legal authority to eliminate a congressionally funded independent agency and that the work of USAID is vital to national security.

Trump and congressional Republicans claim much of foreign aid and development programs are wasteful and single out programs they say advance liberal social agendas.

The Hill and The Associated Press contributed to this report.