Mexico’s biggest Catholic archdiocese says that any of the country’s citizens who help build President Trump’s planned border wall will be immoral traitors.

A blistering editorial in Desde la fe, the archdiocese’s weekly publication published, urged the government on Sunday to push back against companies looking to profit from the wall, Reuters reported.

“Any company intending to invest in the wall of the fanatic Trump would be immoral, but above all, its shareholders and owners should be considered traitors to the homeland,” the editorial said.

“In practice, signing up for a project that is a serious affront to dignity is shooting yourself in the foot,” it continued, noting that the wall would feed prejudice and discrimination.

It also accused the government of responding “tepidly” to the country’s firms that are considering working on the project to gain business.

A spokesman for the archdiocese — centered in Mexico City and presided over by Cardinal Norberto Rivera, the country’s most prominent Catholic cleric — said the editorial represents the views of the diocese.

Last Tuesday, Ildefonso Guajardo, the country’s secretary of economy, said it would not be in the “interests” of Mexican firms to help build the controversial structure.

Mexican cement maker Cemex has said it is willing to provide quotes to supply raw materials for the wall, but will not help to build it, Reuters reported.

Grupo Cementos de Chihuahua, another construction material company, has also expressed its willingness to work on the project.

Beginning on the campaign trail, Trump has long promised a border wall between the US and its southern neighbor, in an effort to prevent illegal immigrants from crossing into the country.

He has repeatedly declared that Mexico would pay for the wall — which the Mexican government has resolutely said it would not do.