MATAMOROS, Mexico — Cuban asylum seeker Yuleydis Caballero has been living in a migrant tenement in this border town for nearly 18 months, waiting for her day in a U.S. immigration court under the Trump administration’s “remain in Mexico” policy. So when she learned that families that recently crossed the border illegally have been released in the United States under the new Biden administration, Caballero’s anger boiled over.

“They tell us to be patient, be patient, be patient. But from where do they want us to draw patience? We have nothing left,” Caballero said. “We don’t understand why Trump was able to change policy one day to the next, but a new president can’t change our situation one day to the next.”

Biden’s suspension of the “remain in Mexico” program — officially known as Migrant Protection Protocols — has left a policy void that is fueling frustration among asylum seekers who say they have tried to follow the rules and navigate ever-changing policies in hopes the United States would consider their petitions for protection. But the sudden surge of migrants crossing the border illegally to take advantage of the opportunity to stay in the United States has left those who have spent months waiting in Mexican border camps feeling disrespected and betrayed.

The Biden administration is preparing a new process to bring asylum seekers with active MPP cases into the United States through a phased-in approach, according to two U.S. officials with knowledge of the plan, which was first reported by BuzzFeed on Thursday.

Eligible migrants would be registered and tested for the coronavirus before entering the United States at three U.S. ports of entry. The rollout would prioritize vulnerable migrants for registration as early as next week — processing about 300 migrants per day, U.S. officials said — before expanding to other ports.

But the plan may be little consolation to the 20,000 asylum seekers in border camps, who remain uncertain how quickly a new process will reach them. Some are already calculating the risks of paying smugglers to help them swim across the Rio Grande or pressuring ports of entry by crossing as one large group.

A 33-year-old Honduran woman, who spoke on the condition of anonymity out of fear for her safety, said she occasionally retreats from her fenced-in encampment to walk along the mesquite-lined riverbank of the Rio Grande, fighting the urge to try to swim across.

Her teenage daughters have been able to stay in the United States as unaccompanied minors after crossing the border a few weeks ago. But she remained behind in Matamoros, hoping that the new president would create a faster, legal route to get her case in front of a U.S. immigration judge. Instead, she’s been left questioning whether a river crossing might be the best route to reuniting with her daughters.

“I walk alone thinking about how my children beg me every day to join them,” the woman said. “Sometimes I consider throwing myself in there to die because the longer I’m here, the more I feel like I don’t want to live anymore.”

The Trump administration announced the Migrant Protection Protocols in December 2018, requiring Mexico to host asylum seekers as they await their hearings in the United States. Some 20,000 asylum seekers have been confined in Mexican tent camps and tenements waiting for hearing dates that largely have not materialized.

On his first day in the White House, Biden suspended Trump’s policy, ordering that no new migrants be added to the “remain in Mexico” process. While those already living in the Mexican border camps had to stay there, some migrants who cross the border illegally have been allowed to stay in the United States.

As word of the policy shift spreads, the flow of illegal migrants into the United States is growing, and people in border camps are growing angry that those who took a faster but illegal route into the United States are being rewarded.

Yet, outcomes for border-crossers have been inconsistent. Although small groups of vulnerable migrants, such as children, pregnant women and medically fragile individuals, have won entry to the United States on a case-by-case basis, the vast majority of border crossers have been turned back to Mexico or have been immediately expelled under a Trump-era emergency public health order that remains in place under President Biden.

An increasing number of migrant families are arriving at the U.S.-Mexico border even as the novel coronavirus pandemic and Mexican and U.S. authorities’ capacity to hold large numbers of adults with children are legally constrained. Arrests and detentions along the border rose to nearly 78,000 in January — an unusually high number for a month in which border apprehensions are typically low, data shows. The number of people who attempted multiple crossings also jumped from January 2020.

Fani Benitez’s husband sent for her last month to join him in the United States, where he has lived since 2017 with their young daughter. Benitez journeyed north by bus from Honduras with the couple’s 5-year-old son, not knowing what to expect once she reached the border. The 27-year-old was expelled after crossing into El Paso, but at the insistence of her family, she tried again farther east.

“I was surprised we made it,” said Benitez, who crossed the Rio Grande by raft late Monday. She was intercepted by U.S. immigration officials but soon was released. Less than 24 hours later, the exhausted woman was waiting in South Texas for a bus to another state.

About a dozen asylum seekers interviewed at the guarded gate of the Matamoros migrant camp this week said they are willing to give the Biden administration time to untangle what is a complicated web of Trump-era policies to avoid chaos at the border. They said that they are accustomed to clinging to the flimsiest promise of a positive outcome but that in the absence of any plans or proclamations, the information vacuum is being filled with rumor.

The cancellation of court hearings because of the coronavirus pandemic was a major blow to morale, and the number of camp residents has declined over months as many have disappeared into Mexico or returned to their countries. The families that stayed have clung for months to the hope of intervention by a lawyer or advocate, a change in the law or the election of a new administration. But the optimism is wearing thin.

And the psychological consequences for camp inhabitants are dire, migrants said. Living in squalid border camps for months has left migrants adults and children in severe mental distress. Limited financial support from relatives over the past year is drying up. The threat of extortion or exploitation by criminal organizations heightens each day.

“This is killing us,” said Oscar Alonso Lopez, a migrant from Nicaragua seeking political asylum. He spoke from behind the razor-wire fencing erected by the Mexican officials around the camp that migrants say makes it feel like a prison. He entered the Migrant Protection Protocols process a year ago to await a court date. “We are ill, emotionally. If covid doesn’t kill us, depression will. The stress drives us to make terrible decisions. I left a prison in my country, seeking justice and liberty … only to find myself in prison again.”

Advocates and lawyers have been scrambling to separate fact from fiction among the rumors and disinformation circulating among migrants from Tijuana to Matamoros. Some shelters known for housing Haitian migrants in Tijuana have emptied out in recent days as families fled to Reynosa, Mexico — across from McAllen, Tex. — because they received messages that their chances of release into the United States were better there. Several Cuban migrants in the MPP program were turned back after trying to cross from Ciudad Juárez to El Paso this week, according to a WhatsApp chat group of asylum seekers across the border in Mexico.

“It has always been arbitrary who is allowed through the U.S. border,” said Conchita Cruz, co-executive director of the Asylum Seeker Advocacy Project. Her group keeps a network of 50,000 asylum seekers updated on immigration policy changes. “The whims of border officials, the capacity of border detention facilities — these are some of the variables that have previously determined whether a family is separated, detained or treated humanely at the border.”

Yoalis Marin has rented housing with other asylum seekers in northern Mexico since arriving in September 2019 from Venezuela with her 8-year-old daughter. Her husband and two eldest daughters are already in Florida after allegedly facing violence in Mexico from armed motorcycle gangs with ties to officials. But after MPP hearings were halted with the onset of the pandemic, she is stuck in a country where she cannot work and says she faces constant danger and is separated from family support.

Luis Guerra, a legal advocate on the border with the Catholic Legal Immigration Network, said it has been challenging to help guide clients or answer questions about whether hearings will occur or be rescheduled, without any concrete answers from the administration in Washington. Most of the group’s work lately involves debunking rumors and giving families the best available information to make decisions. The recent migrant releases into the United States make that job much harder.

“It’s hard to tell people to wait when their situations are unimaginable for most of us who have the privilege of not having to worry about safety, food or proper shelter,” Guerra said. “People need to understand that the previous administration created a fiction of legal process where people were set up to fail. MPP was never actually created for legitimate asylum cases to have a fair chance in court. Remain in Mexico, as its known, is not a matter of waiting in a DMV line, it’s being in a DMV line while you’re actively running for your life.”

Cuban asylum seeker Joel Fernandez Cabrera said the least the Biden administration can do is to send a clear message so that migrants can create their own timelines and plans to find refuge.

“Tell us what is going to happen to us,” he said. “We are in perpetual limbo and we need explanations.”

Nick Miroff in Washington contributed to this report.