Mexicans helping President Donald Trump build his signature campaign initiative, the border wall along the Untied States-Mexico boder, will be acting immorally and should be deemed traitors, Mexico's biggest archdiocese said Sunday.

“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 Catholic Archdiocese of Mexico said in an editorial titiled "Treason against the homeland" in its weekly publication Desde la fe, according to Reuters.

The archdiocese, which centers on Mexico City and is presided over by Cardinal Norberto Rivera, Mexico's foremost Roman Catholic cleric, confirmed that the editorial represents the views of the diocese. A diocese is a district under the pastoral care of a bishop in the Christian Church and an archdiocese is the district, (usually bigger metropolitan area) for which an archbishop is responsible.

Read: Mexican Politician Climbs Border Wall To Show How ‘Absurd’ Trump's Wall Plan Is

“In practice, signing up for a project that is a serious affront to dignity is shooting yourself in the foot… what is most surprising is the timidity of the Mexican government's economic authorities, who have not moved firmly against these companies," the editorial said, according to the Associated Press.

However, contrary to the church's complaint, Mexican government's economic authorities have been warning companies against Trump’s border wall plan. On Tuesday, for instance,  Economy Minister Ildefonso Guajardo told firms that it may not be in their “interests” to participate in the wall.

"We're not going to have laws to restrict (companies), but I believe considering your reputation it would undoubtedly be in your interest to not participate in the construction of the wall," Guajardo said, according to Reuters

"There won't be a law with sanctions, but Mexicans and Mexican consumers will know how to value those companies that are loyal to our national identity and those that are not," Guajardo added.

His comments followed similar warnings by Mexico's Foreign Minister Luis Videgaray, who claimed that Mexican companies seeing a lucrative business opportunity in the wall should "check their conscience" first.

Mexican cement maker Cemex has reportedly said that it will refrain from participating in the bidding process but may be open to supplying raw materials "if a client asks for it." Grupo Cementos de Chihuahua, another company that deals with construction materials in which Cemex holds a stake, has also expressed willingness to take part in the project.

Trump’s border wall project, expected to cost upwards of $20 billion, has been criticized as a frivolous expenditure that will not accomplish its aim to prevent illegal immigration over the southern border, according to several Customs and Border Protection officers, local law officials and immigration experts.