EL PASO — As attention focuses on a migrant caravan moving north through Mexico, communities along the border in Texas are scrambling to help hundreds of Central American families already arriving there each week.

“This is the third surge [of migrants] that we’ve seen over the past three years. Clearly it is the highest, the largest surge that we’ve seen,” said Ruben Garcia, the founder and executive director of Annunciation House, an El Paso nonprofit that has cared for migrants for 40 years.

At the Paso del Norte bridge connecting El Paso and Ciudad Juárez, Mexico, hundreds of Central American parents and children camp out each night, waiting for the chance to apply for asylum at the port of entry. Hundreds more families cross between ports, requesting asylum after being apprehended by Border Patrol agents.

The migrant families are initially detained in holding cells at the bridge or at Border Patrol stations. Built to detain people for a few hours for processing, the holding cells have been used in recent weeks to house 20 or more people at a time for up to three days. Some families have reported being moved from one cell to another, sometimes spending a week or more in detention before being released.

In El Paso, Immigration and Customs Enforcement releases about 2,100 people per week to Annunciation House, which works with area churches to shelter and feed migrant families as they await transportation to join relatives elsewhere in the United States. The rate of release has tripled in the past month, leading Annunciation House to increase the number of churches it relies on.

Garcia said his aim is to create “equilibrium” by increasing Annunciation House’s capacity to match the number of migrant families being detained in holding cells. His agency rents two El Paso motels at a cost of $38,000 a week to help meet increased demand.

“Our goal is to build capacity to be able to end the practice of using these cells as temporary detention sites, where people are bunched up in ways that is very inappropriate and not healthy,” he said.

Garcia said more space should also cut the need for families to sleep on the Mexican side of the bridge as they wait to apply for asylum in the United States. Customs and Border Protection officers have been regularly denying entry to would-be asylum seekers since spring, claiming ports of entry lack the capacity to process more people. The number of people camping on the bridge, however, has started to rise only over the past couple of weeks.

Overnight temperatures in the El Paso-Juárez region regularly dip into the 40s this time of year.

Roger Maier, a CBP spokesman in El Paso, said: “CBP facilities are temporary holding facilities where people are not held for more than 72 hours except in rare, extenuating circumstances. It is a priority of our agency to process and transfer all individuals in our custody to the appropriate longer-term detention agency as soon as possible.”

The cost of caring for the migrant families after their release is borne by churches and Annunciation House donors. The government contributes no money to the effort.

Hundreds of volunteers have flocked to the shelters over the past week, Garcia said.

“It is their commitment that I truly believe personifies, exemplifies, what it really means to be a citizen of the United States,” he said.

CBP statistics show that apprehensions at the border are rising over 2017 levels but still well below the numbers seen in the 1990s and 2000s. The number of families apprehended, however, is at record levels, with 16,658 members of “family units” taken into custody in September at the southwest border.

Officials said 2,676 of those apprehensions came in the Border Patrol’s El Paso sector. That was second only to the Rio Grande Valley, where 8,782 members of family units were apprehended.

Sister Norma Pimentel, executive director of Catholic Charities of the Rio Grande Valley, said her shelter at Sacred Heart Catholic Church in McAllen is now taking in 500 migrant family members a day following their release by immigration officials — up from about 150 a day in late summer.

“I am accepting everybody that’s being released. Border Patrol has been very good about sending them out in groups of not more than 500 so we can manage it as best we can,” Pimentel said.