A Christian pastor and his pregnant wife were killed on their farm in northeastern Nigeria last week, the latest victims in a series of abductions and killings of Christians in the country.

Gunmen shot dead Pastor Emmanuel Saba Bileya and his wife, Julianna, on their farm in Taraba, Northeastern Nigeria, on June 1, according to the Robert E. Webber Institute for Worship Studies where Bileya had been enrolled since 2014. Julianna was pregnant with the couple's ninth child.

Bileya was a pastor in the Christian Reformed Church of Nigeria (CRC-N). He and his wife leave behind eight surviving children, and were buried in Donga on June 5, according to the Hausa Christians Foundation.

A statement released by the state police said that "While they were working on the farm, suddenly armed men came and opened fire on them, leading to the death of the pastor and his wife."

The Hausa Christians Foundation called the killings part of  a "systematic, direct war against Christianity in Nigeria," and said that "pastors, Christian leaders and seminarians are either being kidnapped or killed every week" in the country.

Taraba governor Darius Ishaku called the killings "wicked and inhuman" in a statement to the local newspaper This Day, on June 3. 

"Killings of this nature have happened too often recently in Southern Taraba communities and this is unhelpful to the on-going efforts of the government to achieve lasting peace among communities in the area," said Ishaku.

"I sympathize with the surviving members of Pastor Bileya's immediate and extended families as well as pastors and members of CRC-N in Mararaba where he served until his death."

The attack is the latest in a spate of violence against Christians in Nigeria, largely from the terror group Boko Haram, militant nomadic Fulani herdsmen, and the terror group Islamic State West Africa Province (Iswap) and occurring in the Middle Belt and northeast regions of the country.

More than 600 Christians have been killed so far in 2020, according to a report on May 15 by the International Society for Civil Liberties and the Rule of Law (Intersociety). Christians have been beheaded and set on fire, farms set ablaze, and priests and seminarians have been targeted for kidnapping and ransom.

In January, militants kidnapped four Catholic seminarians from Good Shepherd Seminary in Kaduna and eventually killed one of them, Michael Nnadi. On March 1, Nigerian priest Fr. David Echioda was kidnapped by gunmen after offering Sunday Mass, but was released days afterward.

In an Ash Wednesday letter to Nigerian Catholics, Archbishop Augustine Obiora Akubeze of Benin City called for Catholics to wear black in solidarity with victims and pray in response to the killings and kidnappings.

As the number of Christians killed in the country continues to rise, local leaders have increasingly blamed government inaction to protect lives. The Intersociety report concluded that "atrocities against Christians have gone unchecked," "with the country's security forces and concerned political actors looking the other way or colluding with the Jihadists."

In March, Archbishop Ignatius Kaigama of Abuja, Nigeria, called on President Muhammadu Buhari to address the violence and kidnappings in a homily during Mass with the Catholic Bishops' Conference of Nigeria.

"We need to have access to our leaders; president, vice president. We need to work together to eradicate poverty, killings, bad governance and all sorts of challenges facing us as a nation," Kaigama said.

On Feb. 27, U.S Ambassador at Large for Religious Freedom Sam Brownback told CNA that the situation in Nigeria was deteriorating.

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"There's a lot of people getting killed in Nigeria, and we're afraid it is going to spread a great deal in that region," he told CNA. "It is one that's really popped up on my radar screens -- in the last couple of years, but particularly this past year."

"I think we've got to prod the [Nigerian President Muhammadu] Buhari government more. They can do more," he said. "They're not bringing these people to justice that are killing religious adherents. They don't seem to have the sense of urgency to act."