Hundreds of migrant families will be flown to California in as many as three flights a week as U.S. Border Patrol agents continue to struggle with the growing number of illegals crossing into the U.S., officials said.

Flights carrying 120 to 135 people were set to begin flying Friday to San Diego from the Rio Grande Valley in Texas and would continue to do so indefinitely, Border Patrol's interim San Diego sector chief Douglas Harrison said.

Harrison called it a “contingency operation” that would see at least three flights a week making the trip. Each flight would cost the government around $6,000, officials said.

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“We don’t have an end date,” he said. “We’ve got to give the people in Rio Grande Valley some relief.”

Once taken in at the border, migrants will go through processing where their biographical information will be collected. They will then go through a medical screening before being placed on a flight to San Diego International Airport where they will be transported to a Border Patrol Station upon arrival. There, they will be fingerprinted and interviewed and subject to a second medical screening.

The process of screening and interviewing one person typically takes several hours. Immigration and Customs Enforcement (ICE) will decide whether to release or detain the families in San Diego.

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Border arrests have skyrocketed since Oct. 1, having reached a record 520,000, the highest in a decade, and on average agents make around 4,500 arrests a day, Reuters reported. The Rio Grande Valley, with nearly 8,000 people in detention, is by far the busiest charter followed by El Paso.

Officials have said they are also considering similar flights to Detroit, Miami and Buffalo, N.Y.

The Associated Press contributed to this report.