Last Updated Jan. 25 at 6:53 a.m. ET

After the Trump administration threatened to subpoena 23 states, cities and counties over their immigration policies, several mayors -- including at least one Republican -- backed out of a planned infrastructure meeting with the president on Wednesday.

“Unfortunately, the Trump administration’s decision today to threaten our mayors and demonize immigrants yet again -- and use cities as a political prop in the process -- has made a meeting at the White House untenable for some of us," said New Orleans Mayor Mitch Landrieu, president of the U.S. Conference of Mayors (USCM).

He continued: "The U.S. Conference of Mayors is proud to be a bipartisan organization. But an attack on mayors who lead welcoming cities is an attack on everyone in the conference."

Landrieu, who is rumored to be a potential 2020 candidate for president, and hundreds of other mayors are in Washington, D.C., this week for an annual meeting. The White House had invited more than 100 of them to discuss infrastructure. But around noon, the U.S. Department of Justice announced that it was sending letters to so-called sanctuary jurisdictions requesting documents to show whether they are unlawfully restricting information sharing between their law enforcement and federal immigration authorities.

Attorney General Jeff Sessions is threatening to pull federal funding from cities that do not show compliance, though multiple federal courts have blocked the Trump's administration from doing so.

According to CNN, at least three of the mayors that received DOJ letters were meant to attend Wednesday's meeting: Denver's Michael Hancock, Louisville, Ky.'s Greg Fischer and New York's Bill de Blasio.

De Blasio pulled out.

“I will NOT be attending today’s meeting at the White House after @realDonaldTrump’s Department of Justice decided to renew their racist assault on our immigrant communities,” he tweeted. “It doesn’t make us safer and it violates America’s core values.”

Fischer's spokesperson told CNN he would attend, but the mayor blasted the DOJ letter beforehand.

"This notice today is insisting that people send proof that they are in compliance with federal law, and I would bet that many of us up here have already done that," he reportedly said. "So perhaps the mailbox at DOJ should be checked."

Roughly 100 mayors ultimately attended the meeting, according to Politico.

But Steve Benjamin, mayor of Columbia, S.C., and vice president of the mayors group, wasn't one of them. The only member of the group's leadership who still planned to go was Republican Bryan Barnett, the mayor of Rochester Hills, Mich., who is USCM's second vice president.

At least one Republican mayor is joining the boycott. The spokesperson for Elizabeth Kautz, mayor of Burnsville, Minn., and a former USCM president, told CNN she will sit this one out because of the subpoena threats.

The White House reacted accordingly.

"We are disappointed that a number of mayors have chosen to make a political stunt instead of participating in an important discussion with the President and his administration," said White House Deputy Press Secretary Lindsay Walters.

Chicago Mayor Rahm Emanuel, a former Obama aide, cast doubt on the administration's motivations for sending out the letters the same day of the meeting with mayors, reports USA Today.

"[Trump] didn't want to have a conversation about infrastructure," he said, "because we would all see that the emperor has no clothes when it comes to his plan."

Much of Landrieu's speech focused on infrastructure and the lack of action by the Trump administration. Leaked details of a White House infrastructure plan suggest that federal dollars would only represent about $200 billion, much less than the $1 trillion Trump once pledged.

If true, Landrieu said, "he's committing our country to further erosion and decay instead of fulfilling promises."