Gov. J.B. Pritzker on Friday sent Texas Gov. Greg Abbott a sweeping letter about the ongoing migrant crisis, urging him to halt drop-offs during a dangerous winter storm.

“While action is pending at the federal level, I plead with you for mercy for the thousands of people who are powerless to speak for themselves,” Pritzker said in the letter. “Please, while winter is threatening vulnerable people’s lives, suspend your transports and do not send more people to our state.”

Pritzker wrote that sending migrants to Chicago this weekend — when temperatures are expected to reach dangerously low temperatures after several inches of snowfall — will potentially cost lives. Wind chill values are expected to dip to minus 17 degrees Saturday night.

“Your callousness, sending buses and planes full of migrants in this weather, is now life-threatening to every one of the arrivals,” Pritzker wrote. “Hundreds of children’s and families’ health and survival are at risk due to your actions.”

According to the city’s Office of Emergency Management and Communications, Chicago has received an estimated 34,562 migrants since the drop-offs began. That includes 4,468 people who have arrived on daily flights to O’Hare and Midway international airports since June 2023.

One bus was expected to make drop-offs in the Chicago area Friday, the city said. There are also 408 migrants awaiting placement — with 14,574 people in 28 active shelters.

Pritzker’s strongly worded letter accused Abbott of having “no interest in working on bipartisan solutions to the border crisis because that would put an end to your cruel political game.”

Responding to the letter, Abbott’s office on Friday said Texas will continue to send migrants until the president secures the border. His office also said migrants heading to Chicago signed a voluntary consent waiver and agreed upon the destination — and bus drivers are receiving weather updates and are taking additional safety precautions.

“Instead of complaining about migrants sent from Texas, where we are also preparing to experience severe winter weather across the state, Governor Pritzker should call on his party leader to finally do his job and secure the border — something he continues refusing to do,” Abbott spokesman Andrew Mahaleris said in an email to the Sun-Times. “Until President Biden steps up and does his job to secure the border, Texas will continue transporting migrants to sanctuary cities to help our local partners respond to this Biden-made crisis.”

Chicago’s “landing zone” became a temporary shelter for migrants in late December after the city stopped housing them at police stations. As of Monday, it was housing more than 500 people in buses, including over 100 children, as the number of people arriving has outpaced the city’s ability to place them in shelters.

The state on Wednesday opened a new shelter in the Little Village neighborhood, which can accept 220 people.

The influx of migrants — more than 30,000 sent to Chicago from Texas — has also hit the suburbs, where several communities have enacted ordinances to prohibit bus drop-offs.

Pritzker on Wednesday said the state is trying to prevent companies from leasing their planes to the state of Texas. He said he believes the state has deployed a strategy that is deterring the plane drop-offs.

Illinois has been in contact with airport officials across the state to warn them of the flights.

“We’re trying to prevent those companies from leasing their planes to the state of Texas. You can’t, in general, you can’t tell a group, a people, or an aircraft that it can’t come somewhere,” Pritzker said. “On the other hand, there are lots of things that I think would be a significant deterrent, and they already are working.”

Last year, the state tried coordinating with bus operators and organizations at the border to try to gauge the timing of drop-offs. Results of that effort were mixed.

Pritzker in October tried to publicly pressure the White House to mitigate the crisis, writing in a letter to Biden that Illinois is in an “untenable situation.” That letter led to more frequent communication between Pritzker’s administration and the White House about the crisis.