*Editor's note: This story has been updated to include additional information from Dallas County.

While "sanctuary" policies on immigration enforcement in California and Illinois are getting in the way of the Trump administration's goal of a nationwide crackdown, federal immigration authorities are finding plenty of help in Texas counties, a new report shows.

From January to May of 2017, while the Texas Legislature was debating Senate Bill 4, its own immigration enforcement bill, Texas counties were some of the most compliant when it came to working with U.S. Immigration and Customs Enforcement, according to an analysis released Tuesday by the Migration Policy Institute, a Washington-based immigration think tank.

As passed, SB 4 allows local law enforcement officers to question the immigration status of people they detain or arrest and punishes local government department heads and elected officials who don’t cooperate with federal immigration "detainers" — requests by agents to turn over immigrants subject to possible deportation — in the form of jail time and penalties that exceed $25,000.

The report states that between Jan. 20 and May 4, 2017 — three days before SB 4 was signed into law — the number of people transferred into ICE custody from county jails was 60 percent higher in Harris County than during the same period in 2016, and there was no record of local officials there declining detainer requests during that time frame.

Though its main focus was on Harris County, the report includes statistics from the 25 U.S. counties with the most ICE detainer requests. In Texas, that includes Hidalgo, Bexar, Dallas, Webb and Travis counties. The report shows that Bexar and Webb counties complied with every detainer request they received, while Hidalgo declined only one. Dallas County officials declined 17 detainers, and Travis County officials declined 130. That's compared to 267 declined detainers in New York City, 161 in Los Angeles County and 80 in Illinois' Cook County, which contains much of Chicago.

Randy Capps, the director of research for U.S. programs at the Migration Policy Institute, said the Travis County numbers were likely the result of Sheriff Sally Hernandez’s policy in 2017 to only comply with ICE detainers on a very limited basis. (The office has since amended its policy and now complies with all detainers.)

"We asked ICE about it, and they told us, every place in the state — and this was last year, before SB 4 was passed — was operating except for Austin/Travis County,” said Capps. “Battles between Austin and the state are legendary, and this [bill] was one of those battles.”

A Dallas County jail spokesperson said Tuesday morning that it did not decline any detainer requests in 2017, according to the agency's records, and was unclear how the report's writers came to their conclusion.

The report backs up one argument opponents of SB 4 made during last year's debate over the bill: The legislation wasn't necessary because Texas counties already cooperate with ICE. A 2016 analysis of ICE data by The Texas Tribune showed that out of 18,646 declined ICE detainers from law enforcement agencies around the country between January 2014 and September 2015, only 146 — less than 1 percent — came from Texas.

It all translates into shakier ground for undocumented immigrants in Texas compared to other parts of the country, the report's authors say.

"As MPI’s findings demonstrate, the fortunes of an unauthorized immigrant are quite different in Texas, Tennessee, and Georgia, where the mere act of driving can result in arrest and deportation, than in California, Chicago, and New York, where immigrants can be arrested for a variety of crimes and still not be taken into ICE custody," the report states.

When asked about the 60 percent increase in detainers issued that are cited in the report, Harris County Sheriff’s Office spokesman Jason Spencer said the department hasn’t changed its policy under the Trump administration.

“The Harris County Sheriff’s Office honors ICE detention holds,” Spencer said in an email. “If there has been an increase in the number of detention holds, you would have to ask ICE the reason, since they are the agency generating those holds.”

The report also shows that, though pegged as soft on immigration during his tenure, former President Barack Obama’s immigration enforcement measures in 2013 and 2014 rival those of President Donald Trump. In Texas, there were 2,713 total detainers issued from ICE to the Harris County jail in 2013 and 2014, compared to 1,330 issued in 2017 under Trump during the timeframe of the report's study. And in Dallas and Hidalgo counties, respectively, there were 1,763 and 1,436 detainers issued in 2013 and 2014, compared to 841 and 622 in 2017.

But those numbers dipped significantly in 2015, after the Obama administration issued its Priority Enforcement Policy, which greatly reduced the number of undocumented immigrants eligible for detainer requests. In 2015, Harris County saw just 545 detainer requests, while Hidalgo County saw 481.

“The Trump administration changed their enforcement priorities,” Capps said. “ICE generated fewer holds because of the narrower priorities” under Obama. “Trump signed an executive order reinstating those priorities.”