The UN relief chief on Wednesday warned that allowing the conflict in Sudan to descend into a full-blown civil war could become a human tragedy.

"If urgent international action is not taken, the crisis threatens to deteriorate into a catastrophe that could engulf, will engulf, the entire country and then the region," said UN Under-Secretary-General for Humanitarian Affairs Martin Griffiths, the global body's emergency relief coordinator.

He said a concerted international effort is required to get life-saving assistance. "It is needed now; it was needed yesterday, and it will be needed tomorrow."

Griffiths spoke at a high-level meeting on Sudan on the sidelines of the UN General Assembly's annual general debate.

The session was hosted by Egypt, Saudi Arabia, Qatar, the African Union, the European Union, the UN Refugee Agency and the UN Office for the Coordination of Humanitarian Affairs (OCHA).

One of the biggest challenges during the fighting between two military factions in Sudan is gaining access to those in need.

"Our ability to operate is hampered by the highly dangerous and complex operating environment – perhaps the most so in the world today – as well as access restrictions and bureaucratic impediments," he said.

Griffiths said the conflict has claimed the lives of more than 5,000 people, injured 12,000 more and displaced more than 5 million people, including more than 1 million of them forced into neighboring countries.

He also said there was a complete breakdown of the health system in Sudan, with almost 80 percent of health services not functioning and more than 6 million people facing emergency levels of acute food insecurity.

"And 1,000 – perhaps this is the worst of all these chilling statistics – 1,200 children dying from malnutrition and preventable diseases, such as measles," the relief chief said. "And we heard in the Security Council last week horrific and pervasive levels of sexual violence against women and girls."

Speaking of the conflict between the Sudanese Armed Forces and the Rapid Support Forces, UN undersecretary-general for political affairs Rosemary DiCarlo said that neither warring party is close to victory, yet they continue their brutal fight, and civilians have paid a heavy price for "this senseless violence."

She said they continue to violate international humanitarian and human rights law. Civilians and civilian infrastructure, including health facilities, places of worship, water and electricity installations, were targeted, damaged and destroyed.

"There have been shocking accounts of widespread rape and sexual violence," DiCarlo said. "There must be accountability for these crimes, as well as medical and psychosocial support for survivors."

OCHA, which Griffiths heads, said that since the conflict began in Sudan, the United Nations and partners reached 3.5 million people, representing only 19 percent of the 18 million people targeted for humanitarian assistance and protection.

The Humanitarian Response Plan for Sudan seeks $2.6 billion but is only 31 percent funded.