A Nigerian Archbishop has joined US political leaders in calling on Donald Trump to intervene in the ongoing persecution of Christians in Nigeria. 

Thousands of Nigerian Christians have been killed in attacks by the ISIS-affiliated terrorist group Boko Haram and extremist Fulani herdsmen.  The 2018 Global Terrorism Index estimates that over 1,700 people have been killed by the Fulani this year alone. 

Archbishop of Jos, Benjamin Kwashi, joined Republican congressman Ron Estes and other political leaders at the US Capitol on Wednesday to call on the US president for help. 

Archbishop Kwashi asked for a US envoy to stand in a 'neutral place' of 'authority', and pressure the Nigerian government to protect the lives of all its people, regardless of religion, the Washington Free Beacon reports.

He said the scale of the attacks on Nigeria's Christian community had weakened the country's democracy and 'bedeviled' communities.

'If you look at the geography of the killings from the beginning of Boko Haram, and even before that, you would have noticed that the killings are systematic,' said Kwashi.

'They are deliberative, they are calculated and those carrying them out are well trained. Everyone knows that they are trained either by Al-Qaeda or ISIS. Everyone knows that they are well armed, they kill soldiers, they kill police. They overrun villages ... in the most inhuman ways.'

He added: 'We need an envoy whose heart and voice will carry the weight necessary to stop the killings.  We are [appealing] to the kind-heartedness of the Americans, the energy, the care, and the concern for justice.' 

Congressman Estes said that time was running out to restore peace to the region and eradicate the terrorists. 

'Sadly, Christians in Nigeria are under fire in what many are calling a genocide by sectarian groups like Boko Haram,' he said. 

'It's important to note that Secretary of State Mike Pompeo, Ambassador Sam Brownback, and other government agencies are doing a lot to support peace and stability in this region.  However, we know more can be done to end the violence and save lives.

'The problem is serious and time is running out.'

Other church leaders have also spoken out about the violence afflicting Christian communities in Nigeria. 

The Catholic Bishop of Gboko Diocese, William Amove Avenya, said this week that although they were under constant threat from Boko Haram and the Fulani, 'no one is doing anything about it.' 

He told Aid to the Church in Need that victims of Fulani attacks in his diocese included children and pregnant women.  

'Fulani tribesmen, armed to the teeth, are murdering pregnant women and children, and destroying our smallholdings,' he said. 

'This is a time bomb that threatens to ignite the whole region,' he said. 'We need to ask who is behind this.'

The bishop has previously urged the international community 'not to wait for a genocide to happen before intervening'.