Senior State Department officials have drawn up plans to close a dozen consulates overseas by this summer and are considering shutting down many more missions, in what could be a blow to the U.S. government’s efforts to build partnerships and gather intelligence, American officials say.

The department also plans to lay off many local citizens who work for its hundreds of missions. Those workers make up two-thirds of the agency’s work force, and in many countries they form the foundation of U.S. diplomats’ knowledge of their environments.

The shrinking is part of both President Trump’s larger slashing of the federal government and his “America First” foreign policy, in which the United States ends or curtails once-important ways of exercising global influence, including through democracy, human rights and aid work.

The moves come at a time when China, the main rival of America, has overtaken the United States in number of global diplomatic posts. China has forged strong ties across nations, especially in Asia and Africa, and exerts greater power in international organizations.

Any broad shutdowns of missions, especially entire embassies, would hinder the work of large parts of the federal government and potentially compromise U.S. national security.

Embassies house officers from the military, intelligence, law enforcement, health, commerce, trade, treasury and other agencies, all of whom monitor developments in the host nation and work with local officials to counter everything from terrorism to infectious disease to collapsing currencies.