Washington — The Trump administration on Thursday announced it plans to admit the lowest number of refugees in U.S. history over the next 12 months, placing a cap of fewer than 20,000 spots for millions of people around the world displaced by war, ethnic conflict and other forms of persecution.

The U.S. is planning to resettle no more than 18,000 refugees in fiscal year 2020, which begins next month. The new ceiling represents the third consecutive and lowest ever reduction of spots for a refugee admissions program created in 1980 that has repeatedly come under fire from President Trump and immigration hardliners in his administration.

Since former President Obama outlined a 110,000 year cap for his final year in office, his successor reduced that number to 45,000 in fiscal year 2018 and then to 30,000, the current limit. The new ceiling — which will be officially instituted after the White House consults with Congress — represents the latest effort by the administration to overhaul the nation's legal immigration system.

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A senior administration official said 5,000 spots under the new cap would be allocated to people fleeing religious persecution, while up to 4,000 spots would be offered to Iraqis who have assisted U.S. forces there.

The U.S. would also resettle no more than 1,500 refugees from Central America's Northern Triangle, despite the fact that hundreds of thousands of migrants have journeyed north in recent months from this region comprised of Guatemala, El Salvador and Honduras to seek refuge at the U.S-Mexico border.

The rest of the spots — about 7,500 — would be allocated for refugees who do not fall under the three categories, the official added. The allocations are a departure from previous region-based categories.

Photo taken Aug. 22, 2019, shows a refugee camp for Rohingya in Cox's Bazar, southeastern Bangladesh. Kyodo via AP Images

The administration official said there are "far more" displaced people around the world than the U.S. can resettle. But the official stressed that the "full picture of U.S. generosity" includes different efforts to help displaced people as close to their home countries as possible, not just through granting refugee status.

Under an executive order signed by Mr. Trump on Thursday, the State Department will only resettle refugees to places in the U.S. where both state and local jurisdictions consent to receiving them. The senior administration official said the administration wants refugees to be placed in communities that are "eager" and "equipped" to support their "successful integration" into American society.

Another administration official said the new ceiling will alleviate the historic backlog in the nation's immigration system and allow asylum officers to focus on conducting so-called "credible fear" interviews for migrants who recently crossed the southern border, as well as screenings for those placed in the controversial Migrant Protection Protocols (MPP) program, which has required nearly 50,000 asylum seekers to wait in Mexico while their cases are processed in the U.S.

Asked by CBS News if U.S. Citizenship and Immigration Services (USCIS) should focus on hiring more asylum officers to deal with all these screenings — for both asylum seekers and refugees — instead of just continuing to slash the number of refugee admissions, the official said that is something they are also working on.

Immigrant advocates and Democrats were quick to denounce the move, which they said severely undermines America's longstanding role as a safe haven for people around the world fleeing persecution.

"This administration's eagerness to unilaterally abandon our national commitment to protect people who are seeking safety from persecution, torture, and genocide is sickening," Omar Jadwat, director of the Immigrants' Rights Project at American Civil Liberties Union (ACLU), said in a statement.

"From the Muslim and refugee bans, to the asylum bans, to the severe mistreatment and separation of families seeking asylum, these attacks have been deliberate, disgraceful, and fundamentally inhumane," Jadwat added.