Conservative leaders are saying President-elect Donald Trump will be held to his campaign promises about immigration policy, according to The Hill.

"This was, along with trade, the issue that allowed Donald Trump to mow down 16 other viable and talented and capable contenders in the primary process," Dan Stein, president of the Federation for American Immigration Reform, told The Hill.

"Nobody can bring out, in rally after rally, Americans who lost loved ones because these immigration laws were not enforced … or Americans who lost jobs because of unfair labor displacement," and not follow through on his promises, he added.

According to The Hill, organizations like FAIR, NumbersUSA and the Center for Immigration Studies, are calling on Trump to reject Rep. Michael McCaul as a candidate for Homeland Security secretary because they believe he would be too close to the Republican establishment to go along with their ideas for immigration reform.

Stein and Mark Krikorian, executive director of the CIS, say McCaul has supported "weak" immigration proposals.

Krikorian said those who support immigrants, the "anti-borders activists," have grown stronger under President Barack Obama's administration and the Homeland Security chief must push back.

"There are going to be human chains around (Immigrations and Customs Enforcement) offices. It's going to be that kind of violent opposition. And I hope whoever is DHS secretary won't go wobbly," he said.

McCaul, a Texas Republican, is close with House Speaker Paul Ryan, The Hill notes, and one source close to Sen. Jeff Sessions, Trump's attorney general nominee said, "You could choose an establishment person for any position but that one."

Trump supporters believe Ryan, Vice President-elect Mike Pence and Republican National Committee Chairman Reince Priebus, who are seen as allies politically, could exert too much influence over Trump on immigration issues.

McCaul's spokeswoman Lizzie Litzow told The Hill he "stands staunchly against any form of amnesty" and he also wants to cut off funding to sanctuary cities.

Trump's allies want Kansas Secretary of State Kris Kobach to lead Homeland Security because of his hard-line stance on immigration. Supporters say Kobach would work to limit legal as well as illegal immigration.

Some churches across the U.S. said they would, if necessary, become sanctuaries for illegal immigrants, according to The Daily Beast.

California lawmakers are looking ahead to Trump's potential deportation plans, introducing measures to protect undocumented immigrants, Fortune reported.