Much of the cooperation on immigration enforcement between the U.S. and Mexico has been led in recent months by acting DHS secretary Kevin McAleenan, who has met extensively with Mexican Foreign Minister Marcelo Ebrard and the Mexican ambassador in Washington, Martha Bárcena. McAleenan is planning to step down in the next several weeks, and Trump has yet to name a replacement.Enrique Valenzuela, a Mexican official who works on migration issues in Ciudad Juárez, said Mexican asylum seekers suddenly started arriving in large numbers to the city in August. Now they appear to be the largest group of people seeking refuge in the United States, surpassing Cubans, he said.

At least 2,500 Mexican asylum seekers are waiting at three bridges connecting the city to El Paso, according to Valenzuela. CBP permits just a few families to apply each day, he said.

A year ago, “we didn’t have this exodus of people who wanted to cross,” Valenzuela said. A few Mexicans would arrive and quickly be processed. “Now it’s a flood of people.”

Most come from Michoacán, Guerrero and Zacatecas, Valenzeula said, states bloodied by violence between organized-crime groups.

“Talking to them, you realize that in reality, they are all coming out of fear,” he said. “The great majority fear for their families.”

Unlike the Central American migrants, the Mexicans did not appear to arrive with smugglers, Valenzuela said. Most took buses to the border after hearing through word-of-mouth of other Mexicans who had received asylum, he said.

“They communicate a lot among themselves — a lot,” Valenzuela said. “As a result of this communication, among neighbors, friends and so on, we are getting a constant flow of people from these communities.”

Mexican migrants have set up makeshift refugee camps near the Cordova, Zaragoza and Paso del Norte bridges, with hundreds of small tents crammed onto sidewalks or in parks. Many families are sleeping under sheets of plastic held together by duct tape. The Red Cross, local churches and charity organizations have provided mattresses, blankets, and food. But many of the asylum seekers arrived with almost nothing.

Anna, 29, and her partner, Daniel, 20, await their fate in a tiny blue pop-up tent on a sidewalk crammed with makeshift shelters just a few hundred yards from the Paso del Norte bridge. They share it with their 2- and 3-year-old toddlers, dark-haired girls with ponytails, dressed in pink.

The couple declined to provide their last names, saying they were fearful of reprisals. It has been three weeks since they fled the southern Guerrero state. Now they are No. 35 on the list of Mexicans waiting to be interviewed for entry into the United States.

Life had become increasingly more difficult for the couple, Anna said. Daniel, who works for the Mexican phone company Telmex, was snatched and beaten up last year by a group that mistook him for a rival. In recent weeks their village south of Chilpancingo was caught in the crosshairs of a battle for control of territory involving two criminal groups, she said.

“There’s a war among the cartels,” she said. “That’s when the violence took off.”

The tipping point came when Daniel’s brother was recently kidnapped, she said. He was soon released, but the couple had reported the abduction to authorities.

“We fled for fear of reprisals,” Anna said.

The family took a bus to Juarez and slept outside on the sidewalk for five days until someone gave them the small tent, she said.

“We heard there was an opportunity for refuge, asylum,” she said. Asked where she heard that, she said: “Everything we saw on the news, about the Central Americans who came.”

Like many of the Mexican migrants, the couple has relatives in the United States they hope to join — Daniel’s grandmother, who lives in Denver.

“What they told us is that it’s different over there,” Anna said, looking toward the border. “They have laws. There’s not so much corruption over there.”

A billboard on the other side seemed to beckon, featuring the face and phone number of an immigration lawyer and the words “Asilo Politico” — political asylum.

“The U.S. authorities tell us through the CBP that, with Mexicans, they can’t deny them entry,” said Valenzuela, the state migration official. “At the end of the day, this is the country they are fleeing.”

Sheridan reported from Ciudad Juárez, Mexico, and Sieff reported from Ciudad Hidalgo, Mexico.