A group of governors banded together to protest President Trump's "zero tolerance" immigration policy as the uproar over the separation of migrant children from their parents at the border continues. Some are withdrawing National Guard troops from the south, while others are pledging to withhold resources.

In April, Trump requested National Guard troops — around 2,000 to 4,000 — be deployed to the southern border. His order invoked a federal law called Title 32, under which governors retain command and control of Guard members from their states.

Arizona, California, New Mexico, Texas and Missouri were among the first states to agree to the president's request. At the time, governors from those surrounding states praised Trump for his commitment toward protecting the border.

WHAT TRUMP'S 'ZERO-TOLERANCE' IMMIGRATION POLICY MEANS FOR CHILDREN SEPARATED FROM FAMILIES AT BORDER

"Missourians are grateful to the President for recognizing the need to secure our borders," former Gov. Eric Greitens, R-Mo., said at the time. "We are proud that Missouri troops will play a support role in guarding against terrorism, protecting Americans from cartel violence, and enforcing our immigration laws."

“Anything we can do to further bolster these efforts is good news for Arizona and for our national security,” Gov. Doug Ducey, R-Ariz., agreed.

But some governors, both Republican and Democrat, have since changed their positions after Attorney General Jeff Sessions ordered a "zero-tolerance" policy in April, which has resulted in the separation of nearly 2,000 children from their families within a 6-week period.

TRUMP'S NATIONAL GUARD REQUEST FOR US-MEXICO BORDER DRAWS RESPONSE FROM SURROUNDING STATES

Here's a list of states that are refusing to send National Guard troops and other resources to the U.S.-Mexico border as of June 19.

Colorado

In a June 18 executive order, Gov. John Hickenlooper, D-Colo., forbid state agencies from providing any resources "for the purpose of separating children from their parents or legal guardians on the sole ground that their families are in violation of federal immigration laws."

Hickenlooper called the separation of children from their parents at the border "cruel" and "un-American," adding that it threatens kids' mental and physical health.

The order says state agencies must adhere to federal law, providing services to anyone who is legally entitled despite their immigration status.

“We urge the administration to stop this cruel practice. If the White House won’t act, Congress should. No political end is worth destroying families and traumatizing children," Hickenlooper said, urging lawmakers to support the Keep Families Together Act.

Maryland

“Immigration enforcement efforts should focus on criminals, not separating innocent children from their families,” Gov. Larry Hogan, R-Md., said in a June 18 tweet. The next day, Hogan ordered four crew members and a helicopter to return to its station in New Mexico.

Massachusetts

Gov. Charlie Baker, R-Mass., canceled plans to send a helicopter and military analysts to back up border patrol due to the “inhumane treatment of children," his spokeswoman told The Washington Post on June 19.

New York

Gov. Andrew Cuomo, D-N.Y., said Trump's immigration policies are resulting in "human tragedy" — and New York will have no part in it.

"In the face of the federal government’s inhumane treatment of immigrant families, New York will not deploy National Guard to the border," Cuomo said in a June 18 statement.

The next day, Cuomo announced he was filing a multi-agency lawsuit against the Trump administration for "violating the Constitutional rights of immigrant children and their families" who have been detained and separated at the border. The governor said there are at least 70 children currently being held in federal facilities in his state alone.

Virginia

Gov. Ralph Northam, D-Va., ordered four National Guard soldiers and one helicopter to return from the southwest on June 19.

"Virginia benefits from the important work of securing our border and we have a responsibility to contribute to that mission. However, we also have a responsibility to stand up to policies or actions that run afoul of the values that define us as Americans," he said in an online statement.

Northam said the state would be willing to return resources to the border once the Trump administration puts an end to its current "inhumane" immigration policy.

Fox News' Kaitlyn Schallhorn and The Associated Press contributed to this report.