US President Donald Trump says he will create a White House faith office and has directed Attorney General Pam Bondi to lead a taskforce on eradicating what he called anti-Christian bias within the federal government.

Trump delivered remarks at the National Prayer Breakfast at the US Capitol and used his speech to call for "unity", telling lawmakers his relationship with religion has "changed" after a pair of failed assassination attempts last year.

At a second prayer breakfast in Washington, Trump struck a more partisan tone, took a victory lap for getting "rid of woke over the last two weeks" and announced steps to protect Christians from what he said was religious discrimination.

"The mission of this taskforce will be to immediately halt all forms of anti-Christian targeting and discrimination within the federal government, including at the DOJ, which was absolutely terrible, the IRS, the FBI and other agencies," Trump said.

He vowed Bondi would work to "fully prosecute anti-Christian violence and vandalism in our society and to move heaven and earth to defend the rights of Christians and religious believers nationwide."

The president did not cite specific examples of anti-Christian bias during his remarks but has previously said that the Biden administration used the federal government to target Christians specifically.

Trump signed an executive order to establish the taskforce and its responsibilities, which include recommending steps to terminate "violative policies, practices, or conduct".

Biden's administration announced a strategy in December for countering anti-Muslim and anti-Arab bigotry, and a similar plan to fight antisemitism in September 2023.

The actions could pose constitutional questions about the separation of church and state, with the US Constitution's First Amendment limiting government endorsement of religion.

The president also announced he would create a White House Faith Office, led by Reverend Paula White, who has served as a religious adviser to him for many years.

Trump established a similar office at the White House during his first term and regularly consulted with a tight group of evangelical advisers.

Trump also said he would create a new commission on religious liberty, and criticised the Biden administration for the "persecution" of believers.

"If we don't have religious liberty, then we don't have a free country," he said.