A report on the findings also said that Christians were "subject to ongoing violent attacks" from armed militias and terrorist groups.
The report said blasphemy laws in Nigeria's northern states are used to silence speech and dissent, target Christians and minorities, and "justify so-called 'convictions' without due process."
Nigeria faces complex security challenge: What to know
Nigeria faces a complex security challenge from many different armed groups and thousands are killed annually. But the victims are both Christians and Muslims.
Plus, other attacks also occur as part of conflicts between farmers and herders over dwindling resources like land. Other battles involve ransoms for kidnappings and sectarian tensions.
Trump puts Nigeria on watchlist
President Donald Trump last year designated Nigeria as a "Country of Particular Concern," due to alleged violations of religious freedom. He said Christianity was facing an "existential threat" in Nigeria.
Nigeria, with a population of 237 million people, is roughly divided between a Muslim-majority north and a Christian-dominated south.
Northern Nigeria has remained affected by the decade-and-a-half-long Islamist insurgency led by Boko Haram and affiliates of the "Islamic State" group.
US report on alleged persecutions of Christians in Nigeria
Congressman Riley M. Moore and others from the House Committees on Appropriations and Foreign Affairs recommended establishing a US-Nigeria security agreement to protect Christians, withholding certain US funds also to the cause and repealing Sharia and blasphemy laws, among others.
On Christmas Day, Trump followed through on a threat and ordered a deadly strike on "Islamic State" group affiliate Lakurawa, who he has accused of persecuting Christians.
That strike was in coordination with the African nation's government.
The US has also sent troops to Nigeria to help advise its military on the fight against the insurgency.
Read: Will 'El Mencho's' Death Trigger a New Drug War in Mexico?
Click here to get the latest news updates from Tempo on Google New
