A New York Police Department union boss encouraged members in a letter released Saturday to stand firm with Immigration and Customs Enforcement (ICE) agents during Sunday’s planned raids.

The letter, written by Sergeants Benevolent Association President Ed Mullins, states that although members of law enforcement do not write the laws, it is their job to enforce them.

He wrote:

We, the members of law enforcement, do not write these laws, nor do we engage in the politics and or opinions of the laws under the United States Code, New York State Penal Law or City Code. Our job is to simply enforce all laws equally upon all individuals so that each person receives equal justice under the law.

Mullins told officers never to “participate in the politics being applied upon our duty to uphold the law,” adding that “I therefore remind you of our sworn oath to uphold the Constitution of the United States and the State of New York.”

However, Baltimore Mayor Jack Young announced Friday that his city would not cooperate with ICE agents during the raids planned for Sunday, Breitbart News reported.

“I said that we were not going to engage with ICE in the deportation or apprehension of any immigrants in the City of Baltimore,” Young said during a protest rally outside City Hall.

Presidential candidate Sen. Kirsten Gillibrand (D-NY) said during an interview Saturday that President Trump’s planned ICE raids are “absolutely unconscionable.”

She commented:

Well, first of all, we don’t know who the target of these raids are going to be. We don’t know if these are DACA kids, DREAMers who came here through no fault of their own, with their parents, who are now serving in our military or going to college or working in our communities. He is indiscriminate. He also doesn’t want to protect the men and women in our military who might have a family member who’s undocumented. There’s always been a view that you will not disturb the family of a service member because they’re fighting for our country, and they’re sacrificing everything. But not under President Trump. So, I’m very concerned about who he’s going to round up, who he’s going to send away, and what basis he has.

However, the president tweeted in June that the individuals who will be subject to the raids are those in the country illegally who have not shown up for their scheduled court dates.

“The people that Ice will apprehend have already been ordered to be deported,” he wrote. “This means that they have run from the law and run from the courts. These are people that are supposed to go back to their home country. They broke the law by coming into the country, & now by staying.”