The United States has ignored India but placed Nigeria for the first time on a religious freedom blacklist, pressing an ally as Christian groups voice growing insecurity.

Secretary of State Mike Pompeo designated Nigeria as a "Country of Particular Concern" for religious freedom, the rare inclusion of a fellow democracy in the US effort to shame nations into action. "These annual designations show that when religious freedom is attacked, we will act," Pompeo, an evangelical Christian, wrote on Twitter.

Nigeria maintains a delicate balance between Muslims and Christians, but church groups have expressed their rising concerns to the United States.

US law requires designations for nations that either engage in or tolerate "systematic, ongoing, egregious violations of religious freedom."

The nations on the blacklist include Saudi Arabia and Pakistan, which both have historic albeit complicated alliances with the United States, as well as China and Iran, arch-rivals for President Donald Trump's administration.

The other nations on the list are Eritrea, Myanmar, North Korea, Tajikistan and Turkmenistan.

Pompeo notably did not target India, an increasingly close partner of the United States.

India voiced outrage earlier this year when the US Commission on International Religious Freedom, which provides recommendations to the State Department, called for India's blacklisting over what it said was a sharp downturn under Prime Minister Narendra Modi, a Hindu nationalist.

Sudan, which is transforming after decades of dictatorship, exited the blacklist last year, and Pompeo on Monday lifted the country from a second-tier watchlist along with Uzbekistan.

Under US law, nations on the blacklist must make improvements or face sanctions including losses of US assistance, although the administration can waive measures.

- Worries about Nigeria worsening -
The State Department did not immediately elaborate on why it designated Nigeria but, in its annual report earlier this year, took note of concerns both at the federal and state levels.

It pointed to the mass detention of members of the Islamic Movement in Nigeria, a Shiite Muslim group that was banned last year on terrorism allegations.

The movement has taken inspiration from Iran, ordinarily a major target for Trump. But the Catholic Church criticized the prohibition on the group, fearing it set a dangerous precedent for all religions.

The State Department report also highlighted the arrests of Muslims for eating in public in Kano state during Ramadan, when Muslims are supposed to fast during daylight hours, and new regulations on preaching in Kaduna state.

Nigeria is the base of Boko Haram, the extremists whose 11-year insurgency has killed more than 36,000 people and spread to neighboring countries.

But the US Conference of Catholic Bishops, in a letter to Pompeo, said that far more Nigerians were being killed in herder-farmer conflicts, in which Christians have borne the brunt as climate change worsens desertification.

Christian groups have also accused President Muhammadu Buhari of paying insufficient attention after jihadists abducted and killed a pastor, Lawan Andimi.

The International Committee on Nigeria, an advocacy group, has urged the United States to appoint a special envoy, calling the Buhari government's response to the violence "weak" and voicing fear it will worsen.

- Bipartisan push on blasphemy -
Religious freedom has been a core issue for Pompeo and Trump, who count on strong evangelical Christian support and have often played down other human rights concerns among allies.

In a bipartisan effort as Trump exits, the House of Representatives overwhelmingly approved a resolution Monday that asks the United States to put a priority on repealing blasphemy laws around the world.

The resolution noted that more than 70 countries had blasphemy laws on the books and voiced alarm over Pakistan as well as about attacks on secularist writers in Bangladesh.

The House also unanimously approved a resolution calling for an end to Iran's "state-sponsored persecution" of the Baha'i community and urged the immediate release of detained members of the faith.