With South Sudan facing the worst refugee crisis in Africa, and increased violence which risks escalating into ethnic genocide leaving a major crisis in northern Uganda, one London-based Christian charity is doing all it can to help those affected.

Hope Health Action (HHA) has been on a mission in the region, having initiated work in South Sudan last year. Its entire South Sudan board and local partners have now been displaced and are urgently calling for assistance from their UK counterpart.

HHA CEO Carwyn Hill has just returned from northern Uganda, where he visited a number of refugee camps to see for himself the situation on the ground. There had recently been a mass exodus from the South Sudanese town of Kajo-Keji, where according to refugees Hill spoke to, there had been acts of 'unimaginable violence'.

'In mid-January it is reported that Government troops raped a lady called Jane in the local area, subsequently killing her and then burning her body,' Hill has written on a blog for the HHA website. 'At a similar time an elderly disabled man was deliberately killed. These were just two incidents we have heard of, from several indiscriminate killings that took place and which have been verified we're informed by many witnesses. Many of the photos we were shown were too graphic and heart breaking to share publicly, scenes of such evil that they're hard to comprehend, standing in stark contrast to the humble, loving and peaceful refugees we have met.'

The latter sentiment was amplified by the role of local faith leaders, who petition the government and pray for the victims.

Hill tells Christian Today: 'Last year when we went to South Sudan we found it inspiring how almost daily different faith leaders all came together to have these meetings and to write letters and petitions calling for peace, and then that came to a head in the middle of January when a number of indiscriminate killings took place by soldiers.' Of the brutal rape and murder of Jane, he said that 'hearing the testimonies of people, of how the various faith leaders came round to pray, was moving and inspiring at the same time'.

Hill, who was hosted by local refugees, says he was 'shocked' at the situation and the crisis. The camp he visited had 144,000 people, and this was just in one of many zones across northern Uganda. Some 1.5 million people have been displaced in what is the third worst refugee situation in the world. South Sudan is facing the first famine to have been declared globally in six years, immediately affecting more than 100,000 people, with a further 1 million on the brink of starvation. Aside from the refugee crisis contributing to the world's largest figures of displaced persons since records began, South Sudan is one of four countries facing the worst humanitarian crisis since the 1940s.

'The scale is pretty harrowing,' Hill says. 'In every area – water, health, everything – they are stretched beyond capacity, with needs outweighing resources. Every family we spoke to had a harrowing back-story.'

The charity leader is determined still to help those who have not made it to the camps. 'One of the areas we are looking to respond to is nutrition for internally displaced people who are still in Kajo Keji,' he says.

Despite the major challenges, Hill has been encouraged by the opportunities to help. 'Wherever you look, the needs are great, regardless of the sector, but we've been encouraged by those on the ground, including the refugee communities themselves who are keen to assist and overcome these immense obstacles. '

HHA is working to equip its displaced local team and partners from South Sudan with the resources to respond to this unfolding crisis and is calling for support from those in the UK.

On one of his blogs, Hill describes horror stories from the camp, including a young man who had just hanged himself.

One hospital administrator Hill met told him, 'The devil's come down,' which Hill says is 'the best analogy I've heard describing this broken, desperate crisis'.

There was a 'but', however. 'The devil's come down, but he's not in control, we have the authority and power,' the hospital administrator said.

Hill concludes: 'These are a truly amazing, courageous and resilient people, and HHA will stand with them as the other agencies here are seeking to do alongside the Ugandan authorities. This is a crisis none of us can afford to turn away from, and despite the efforts of those on the ground helping, more support is critically needed.'

Hope Health Action can be found at www.hopehealthaction.org