LOS ANGELES — The Biden administration on Wednesday designated the nation’s schools and hospitals, as well as a wide array of other locations, off limits to immigration enforcement, the latest sign that it is committed to protecting millions of undocumented residents from deportation while efforts to offer them a path to legalization remain stalled in Congress.

The new guidelines, effective immediately, list “protected areas” where immigration agents are to refrain from making arrests, conducting searches, serving subpoenas or carrying out other enforcement actions.

The sites include schools and university campuses; hospitals, clinics and other medical facilities, in addition to Covid-19 testing and vaccination sites; places of worship; and sites where children gather, such as playgrounds, day care centers and foster care facilities.

The new list is significantly longer and more specific than the one put in place during the Obama administration in 2011, which barred enforcement actions at schools and churches. President Donald J. Trump largely ignored that policy, often leading to indiscriminate arrests.

“Individuals should not be restrained or limited in their access to essential services,” said Alejandro N. Mayorkas, the homeland security secretary, in an interview on Wednesday before the official announcement.

“Children should not be afraid to go to school. Their parents should not be scared to drop them off or pick them up,” he added.

Other protected sites include shelters for victims of domestic violence and homeless people, drug and alcohol treatment facilities, food pantries and sites offering help to those fleeing natural disasters. Immigration enforcement action is also to be avoided at or near funerals, parades and demonstrations.

The guidelines represent the third policy issued by the Biden administration in recent weeks with the goal of bringing “greater humanity” to immigration enforcement, Mr. Mayorkas said.

They mark a profound shift in interior enforcement, and are intended, he said, to improve the day-to-day lives of millions of undocumented immigrants.

Most of the 11 million undocumented immigrants in the United States have lived here for a decade or longer, often with U.S.-born children and deep ties to their communities. About two-thirds of undocumented adults participate in the work force, according to the Pew Research Center.

A memo detailing the policy, which applies to field agents for Immigration and Customs Enforcement and Customs and Border Protection, said that agents must “to the fullest extent possible” refrain from enforcement action in the types of locations on the list “at all times.”

Any exceptions must be approved by agency headquarters, the memo said.

The guidelines come as Democrats continue to struggle to add immigration provisions to a sprawling social safety net and climate bill. Possibilities include offering protected status without citizenship to some undocumented people, and allowing immigrants who have been in the country more than a decade to apply for permanent legal residence.

Since taking office, President Biden has moved away from his predecessor’s tough approach to illegal immigration; the new guidelines are the most recent in a series intended to soften interior enforcement, away from the nation’s border regions.

This week, two House Republicans sent a letter to Mr. Mayorkas demanding answers about the changes in enforcement priorities.

Representative Andy Biggs of Arizona deemed the new approach “an affront to the rule of law.”

“Instead of preventing ICE from enforcing the law, the Biden administration should be empowering them to keep our country safe,” he said in a statement.

Mr. Biden has kept in place some of the border policies introduced by Mr. Trump to staunch the influx of unauthorized migrants at the border. Still, border officials encountered a record 1.7 million migrants in the fiscal year that ended Sept. 30.

During the Trump administration, many undocumented immigrants refrained from spending time outdoors with their children and limited outings to a minimum, typically to buy groceries and go to work, knowing that they could be apprehended even if they had not committed a crime.

Mr. Trump rejected the prosecutorial discretion that former President Barack Obama had exercised in enforcing immigration, instead making everyone who was in the country unlawfully vulnerable to deportation.

Mr. Mayorkas, who has presided over the new enforcement strategy, issued the first set of new interior priorities last month, directing agents at Immigration and Customs Enforcement to target for removal from the country only migrants who had recently crossed the border or people who posed a threat to public safety.

Last week, Mr. Mayorkas announced the suspension of work-site raids that can result in the arrest, and eventual deportation, of thousands of undocumented workers. The mass roundups, often at food processing plants, were a staple of immigration enforcement during the Trump administration.

“We must take a look at the population unlawfully in the country and recognize their significant contribution and presence for many years,” said Mr. Mayorkas, adding that the administration needs to adopt policies that protect undocumented immigrants since Congress has failed thus far to grant them legal status.

But while the latest steps are likely to win praise from immigrant advocates, it is unclear whether rank-and-file ICE officers, many of whom favored the crackdown imposed by the former administration, will comply.

“ICE and C.B.P. have openly and brazenly defied guidance in the past,” said Chris Newman, the legal director of the National Day Laborer Organizing Network, which has led a fight against local police collaborating with immigration authorities.

“In addition to outlining and expanding sensitive locations, the secretary should take steps to rein in the rogue agents charged with implementing the new priorities,” he said.

Mr. Mayorkas said that implementation would be achieved through training, management and supervision of the agents.

The Biden administration has drawn sharp criticism from immigrant advocates who are frustrated that he has not made progress toward fulfilling his campaign promise to offer a permanent legal solution to undocumented immigrants during his first year in office.

Immigrants and their allies have been holding demonstrations across the country, from Washington, to Los Angeles, in recent weeks to pressure Democrats to include a path to citizenship in the social safety net and climate bill.

Protesters blocked traffic last Thursday on San Francisco’s Golden Gate Bridge during morning rush hour, demanding that Senate Democrats “take immediate action to protect all immigrant families,” according to a statement from organizers.