"In the Nuba mountains, we are being bombed daily," says Bishop Macram Max Gassis of El Obeid in Sudan. "Children and women are being hurt ever day. There is no medicine. The Catholic hospital which started with only 80 beds a few year ago now has 300 beds for 500 persons. There are matresses in corridors and large tents outside to help staff match the growing needs."

The Bishop is at the UN in New York to speak with diplomats and UN organisations on the silent crisis in his country. His diocese covers South Kordofan, Abyei and Darfur in Sudan. People in all three places face dire conditions caused by conflict.

He speaks with great sadness about events in Abyei. In early summer 2011, violence erupted on the border between Sudan and South Sudan. Families left everything behind them as they ran to escape aerial attacks, shooting, and house-burnings. Bishop Gassis says the town was completely destroyed, the parish church mindlessly vandalized.

Meanwhile, the situation in South Kordofan remains bleak. The Nuba people live there. It is a north Sudanese border state rich in oil, gold, copper and agricultural produce and was the main oil-producing state left in the north when South Sudan seceded.

In June 2011, Khartoum unleashed an assault on the Nuba Mountains. Nobody has been spared, says the Bishop. Daily attacks with military aircraft target peaceful Nuba civilians, killing and maiming and forcing the mass movement of thousands.

No aid is allowed in by the Sudanese government. At least 1.5 million people in South Kordofan and the Blue Nile are in appalling circumstances, many surviving on roots and leaves.

"The Government of Sudan must open the doors to relief," says Bishop Gassis. "The international community must push for air and land corridors to get aid through to people in desperate need. It is immoral to deny aid to people in need."

During a briefing with other aid agencies, faith based organisations, experts and officials at the UN Church Centre, the Bishop said, "These are God's people. See what I see. Recognise our sisters and brothers. Urgently add your voices to mine so they are not forgotten, lost, ignored. Pray for them. Put charity into action."

The bishop says that the international community must put pressure on Khartoum to immediately stop bombing the Nuba mountains. But he says that their continued silence is a sign of tacit approval of the military campaign.

"Why does the international community feel impotent in the face of such bloodshed," says Bishop Gassis. "Why have they left the Nuba people in the lion's mouth to be devoured."

The Catholic Church and Caritas are helping by proving food, medicine and healthcare through the Mother of Mercy Hospital, the only operating hospital in the area. But the hospital director says there are shortages of vaccines, especially for leprosy and TB, and anti-malarial drugs. The director says even basic supplies like gauze are scarce.

"Caritas is playing a major role in bringing hope to the people of South Kordofan," said the Bishop, and that the hospital staff of religious sisters, priests, local and international staff are "heroic".

However, he says the Catholic Church should be doing more. "Where are the international appeals for the Nuba people, where are the prayers," he said. "The Catholic Church is listened to in Khartoum. We must insist on an end to the fighting and that aid be allowed in."

Bishop Gasis was at the UN last year, with a very similar message. Despite lack of international action, he says he is not giving up. "God will not abandon his people," he says. "Although it is difficult and disheartening, we always have hope."