Hundreds of immigrants have been dropped off by U.S. Immigration and Customs Enforcement at a bus station in downtown El Paso and hundreds more may be released in the southwest Texas city in coming days, reports the CBS affiliate there, KDBC-TV. El Paso's outgoing and incoming representatives in Congress and local charity officials said ICE didn't give the city and charities time to prepare to handle the migrants.

ICE fired back, blaming Congress for the sudden releases.

ICE bussed 214 migrants to the depot Sunday night and some 200 more throughout the day Monday, which left El Paso's Office of Emergency Management and charities scrambling two days in a row, KDBC said.

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Greyhound told CBS News ICE sent the first group "without warning" and did something similar on Oct. 26.

Volunteers came to the bus station to donate and hand out food and other items as arrangements were made to bring the migrants elsewhere.

Rep. Beto O'Rourke, a Democrat, said in an interview posted on Twitter, "We're trying to ensure that ICE gives the community notice next time when they know that there's not going to be space in existing migrant shelters, to give the community 24-hours head-up" so it can prepare.

"We expect another 200 on Christmas Day and it's very possible we'll see another 200 released the day after Christmas, pushing the existing available shelter capacity beyond its limits," he said.

Our thanks to everyone in the community who has come out on Christmas Eve to help migrant families. If you're not in El Paso and want to help, make a donation at https://t.co/062olx7YIp pic.twitter.com/Lm6oEigME2 — Beto O'Rourke (@BetoORourke) December 25, 2018

O'Rourke also said, "ICE admitted that they made a mistake" in failing to notify local and charity officials of its plans so they could "have those beds ready so we don't have migrants standing at a park, or in a parking lot or at a bus station" without food.

"We just need a little bit of a heads up so that folks aren't … literally dumped at a bus station without money or on the street," O'Rourke said.

"We're a little perplexed because this is not something typically that ICE does," said Dylan Corbett, director of Hope Border Institute. Corbett said the federal agency usually communicates with Annunciation House, a nonprofit shelter, so it's prepared for large intakes.

O'Rourke's replacement, Rep.-elect Veronica Escobar, also a Democrat, released a statement saying in part, "The lack of community coordination by ICE … demonstrates a reckless disregard for very vulnerable people, including children. It is unacceptable."

ICE countered by pointing at lawmakers, saying in a statement, "After decades of inaction by Congress, the government remains severely constrained in its ability to detain and promptly remove families with no legal basis to remain in the U.S. To mitigate the risk of holding family units past the timeframe allotted to the government, ICE has curtailed reviews of post-release plans from families apprehended along the southwest border.

"ICE continues to work with local and state officials and NGO partners in the area so they are prepared to provide assistance with transportation or other services."

O'Rourke didn't run for re-election, instead challenging Republican Texas Sen. Ted Cruz for his seat. O'Rourke lost but impressed observers by only falling about three points short in a heavily Republican state and with his fundraising prowess and ability to draw and excite crowds.