SAN FRANCISCO — White House officials on Monday unveiled plans to increase federal funding for the development of artificial intelligence and quantum computing, two cutting-edge technologies that defense officials say will play a key role in national security.

The funding, part of the Trump administration’s $4.8 trillion budget proposal, would direct more money for A.I. research to the Defense Department and the National Science Foundation. The administration also wants to spend $25 million on what it calls a national “quantum internet,” a network of machines designed to make it much harder to intercept digital communication.

For several years, technologists have urged the Trump administration to back research on artificial intelligence — which could affect things as diverse as weapons and transportation — and quantum computing, a new way to build super-powerful computers. China’s government, in particular, has made building these machines a priority, and some national security experts worry that the United States is at risk of falling behind.

The proposed spending follows earlier administration moves. In 2018, President Trump signed a law that earmarked $1.2 billion for quantum research. The Energy Department recently began distributing its portion of that money — about $625 million — to research labs in industry, academia and government.