The Biden administration has directed U.S. border officials to suspend patrols by agents on horseback in the Del Rio, Tex., migrant camp, White House press secretary Jen Psaki told reporters Thursday.

Psaki said Homeland Security Secretary Alejandro Mayorkas told civil rights leaders Thursday morning “we would no longer be using horses in Del Rio.”

“So that is something, a policy change that has been made in response,” she said, describing the administration’s reaction to anger from Democratic lawmakers, rights groups and others over widely circulated images showing U.S. agents on horseback charging at migrants, including families, in an attempt to drive them back to Mexico, while cursing and swinging reins in the air.

The Department of Homeland Security had previously announced that the incident was under investigation and that the agents recorded in video footage have been placed on administrative duties.

DHS officials told reporters during a separate briefing Thursday that the measure was temporary.

“We’ll prioritize other methods for identifying individuals who might be in medical distress,” one official said during a conference call. Reporters were allowed to participate on the condition that none of the speakers could be named.

Border Patrol union representatives did not immediately respond to requests for comment, but they have defended the agents’ conduct, which they say was consistent with their training as federal law enforcement officers.

The images from the Del Rio riverbank Sunday generated a vehement backlash to President Biden’s immigration policies from core supporters who likened his enforcement approach to the Trump administration’s, despite campaign promises to be more humane.

Biden’s decision to ramp up deportations this week has also angered many immigrant advocates and members of the Haitian American community, who led street protests Wednesday in Miami calling for a halt to the flights.

Six more flights carrying returnees to Haiti were scheduled for Thursday, according to public information available on flight tracking sites. The flights typically carry 100 to 120 returnees, including family groups with children.

DHS officials told reporters only about 4,000 migrants remained in the Del Rio camp Thursday morning, down from a peak of nearly 15,000 on Saturday.

More than 1,400 migrants have been returned to Haiti so far, and 3,200 have been transferred to other areas of the border with more capacity to process them. Asked repeatedly how many of the migrants have been released into the United States, the officials said that they did not have the figures available and that it could take several weeks for the data to be ready.

About 3,000 migrants are being processed in the Del Rio Sector, and immigrant advocacy groups there say they are receiving hundreds daily who are being released from custody and allowed to remain in the United States.

The DHS officials said that migrants who cannot be expelled to Haiti under Title 42 of the U.S. public health code would be subject to standard immigration proceedings. In most cases, that means the migrants seeking asylum or some form of humanitarian protection will be released and issued a notice to appear in court or asked to report to federal immigration officials once they reach their U.S. destination.

DHS officials do not have a clear formula to determine which migrants are sent back to Haiti and which ones are allowed to stay. “We have a mix of processing pathways,” one official said, describing a “case-by-base review” of factors that include Border Patrol holding capacity and the individual vulnerabilities of the migrants themselves.

Enforcement data shows single adult migrants are far more likely to be expelled than migrants in family groups, but the return flights to Haiti this week have carried both. DHS officials told reporters they did not have a detailed breakdown available.

About two-thirds of the 15,000 migrants who reached the camp arrived as part of a family group, one DHS official said.

The official said agents have observed thousands of migrants abandoning the Del Rio camp and returning to Mexico since the Biden administration began placing Haitians on the expulsion flights to their home country. The DHS officials could not provide a precise number.

Many of the Haitians are desperate to avoid being sent back to their destitute homeland. Haiti’s government remains in turmoil after a presidential assassination in July and a 7.2-magnitude earthquake in August.

The officials said the U.S. State Department is urging Brazil, Chile and other nations to take back Haitian migrants who were living in those countries before attempting the journey to the United States.

The officials said authorities have set up a temporary medical facility in the Del Rio camp as well as some shelter for vulnerable groups such as pregnant women.

Mayorkas told reporters Monday the Biden administration intends to empty the camp by the end of the month.