President Donald Trump has given his blessing for Bible literacy classes in US schools.

A growing number of states are proposing bills that would allow optional classes on the Bible to be taught in public schools.

Critics say such measures may violate constitutional separation of church and state, and that they serve to impose Christian beliefs on children.

Evangelical Christians make up a loyal part of Trump's base, and he previously told evangelical leaders in the White House that the government's "attacks on communities of faith" are over during his presidency.

President Donald Trump has advocated for what he called "Bible literacy lessons" in US schools.

"Numerous states introducing Bible Literacy classes, giving students the option of studying the Bible. Starting to make a turn back? Great!" Trump tweeted after a "Fox and Friends" discussion of the topic.

USA Today reported last week that a growing number of US states are introducing bills that would allow more students in public high schools to study the Bible.

There are proposals in at least six states that would make public schools offer optional classes on the Bible's literary and historical significance, according to the American Civil Liberties Union (ACLU).

Trump. AP Photo/Jose Luis Magana

Bible literacy bills were introduced in Florida, Indiana, Missouri, North Dakota, Virginia, and West Virginia in 2019, according to the ACLU, which said Bible literacy bills were considered in Alabama, Iowa, and West Virginia last year, but did not pass.

The "Fox and Friends" segment featured North Dakota state Rep. Aaron McWilliams, a Republican who is cosponsoring the measure in North Dakota to support Bible literacy classes.

Critics of such bills say that such measures come close to violating or may violate US constitutional separation between church and state.

"State legislators should not be fooled that these bills are anything more than part of a scheme to impose Christian beliefs on public schoolchildren," Rachel Laser, president and CEO of Americans United for Separation of Church and State, told USA Today.

The proposed bills are linked to an initiative called Project Blitz that is coordinated by a variety of conservative Christian groups, including the Congressional Prayer Caucus Foundation and the National Legal Foundation, USA Today reported.

In Kentucky, a bill was signed into law that allowed public schools to add Bible literacy classes in 2017.

The ACLU said that it investigated the courses and "uncovered public school teachers using the Bible to impart religious life lessons" and other "practices which fall far short of constitutionally-permissive academic and objective study of the Bible and its historical context or literary value."

Evangelical leaders and other faith leaders pray with Trump in the Oval Office. Kevin Lamarque/Reuters

In response, the Kentucky Department of Education released draft academic standards for the optional courses.

Trump professes to be religious and has previously taken issue with what he has perceived to be a slight to Christian traditions. During his campaign, one of his promises was to end the "war on Christmas," even filling campaign rallies with "Merry Christmas" signs.

Evangelical Christians make up a loyal part of Trump's base, and he told evangelical Christian leaders in the White House in August 2018 that the government's "attacks on communities of faith" are over.