WASHINGTON — US President Trump has issued a proclamation, effective Nov. 3, ordering consular officers to bar immigrants seeking to live in the United States unless they “will be covered by approved health insurance” or can prove that they have “the financial resources to pay for reasonably foreseeable medical costs.”

“The United States government is making the problem worse by admitting thousands of aliens who have not demonstrated any ability to pay for their health care costs,” he wrote, adding, “immigrants who enter this country should not further saddle our health care system, and subsequently American taxpayers, with higher costs.”

The surprise order is a step to limit what they consider the financial burdens of allowing immigrants into the United States.

After years of effort by Mr. Miller, the administration issued a regulation in August that would allow officials to deny permanent legal status to immigrants who are poor. The regulation, which imposes an aggressive wealth test on legal immigrants, has been delayed because of several legal challenges.

Under that policy, known as the “public charge” rule, immigrants seeking to live permanently in the United States could be denied if officials deem it is likely they will be a burden on society by, for example, being unable to pay for health care or seeking food and housing assistance.