By Michelle Nichols
UNITED NATIONS, May 8 (Reuters) - The United Nations accused both government and rebel forces in South Sudan on Thursday of committing crimes against humanity, including murder, rape and other sexual violence, during almost five months of fighting that has left thousands of people dead.
"The consequences for the civilian population have been devastating. There have been attacks on hospitals, churches, mosques, and United Nations bases," the U.N. peacekeeping mission in South Sudan (UNMISS) said in a human rights report.
The 62-page report called for further investigations after finding reasonable grounds to believe both parties in the conflict had violated international human rights and humanitarian law.
Violence erupted in the world's newest nation in December, between troops backing President Salva Kiir and soldiers loyal to his sacked deputy, Riek Machar.
The fighting has exacerbated ethnic tensions between Kiir's Dinka tribe and Machar's Nuer tribe, and the United Nations has warned that it risks spiraling into genocide.
"The number of civilian casualties is high, likely in the thousands, although to date no one has been able to establish an exact figure. A dismal pattern of violence and destruction has emerged as the two parties to the conflict gain and lose control of towns and surrounding areas," the report said.
These violations included extrajudicial killings, enforced disappearances, rape and other sexual violence, arbitrary arrests and detention, targeted attacks against civilians not taking part in the fighting, violence aimed at spreading terror among civilians, and attacks on hospitals and U.N. peacekeepers.
"In light of the widespread and systematic nature of many of the attacks, and information suggesting coordination and planning, there are also reasonable grounds to believe that the crimes against humanity of murder, rape and other acts of sexual violence, enforced disappearance, and imprisonment have occurred," found the report.
Several Security Council members on Friday called for the situation in South Sudan to be referred to the International Criminal Court after receiving a briefing on the conflict.
HATRED 'EXTREMELY DEEP'
The United States this week imposed sanctions on two people - one from each warring party - and is pushing the U.N. Security Council to also "authorize targeted sanctions against those who continue to undermine South Sudan's stability," U.S. Ambassador to the United Nations, Samantha Power, said on Tuesday.
Machar arrived in the Ethiopian capital Addis Ababa earlier on Thursday to meet Kiir, a rebel source said, as both sides faced strong international pressure to negotiate to end the conflict.
U.N. peacekeeping chief Herve Ladsous is due to brief the council on the situation in South Sudan later on Thursday.
Hilde Johnson, head of the U.N. mission in South Sudan, told Reuters in Juba on Thursday that the violence had "put the country back decades" and if the fighting did not stop soon, the damage to the country could be "irreversible."
"The hatred is already actually extremely deep and it's going to be a very significant challenge to bridge those differences, to overcome them and to build a nation," she said.
The Security Council needs to renew the mandate for the U.N. mission by July. In December, it approved almost doubling the number of peacekeepers to 12,500 troops as violence worsened but so far, less than half of the 5,500 reinforcements have arrived.
The UNMISS report recommended: "Efforts to protect civilians must be enhanced. UNMISS' capacity should be strengthened, notably the additional troops authorized by the Security Council must be urgently deployed."
U.N. peacekeepers are protecting nearly 80,000 civilians at bases around the country in "the first instance of any United Nations mission providing protection to civilians facing imminent threat of physical violence on this scale or for this length of time," according to the report.
However, it warned that the U.N. mission continued to receive reports that when civilians leave the U.N. bases, they "have been subjected to ill-treatment, sexually assaulted, arbitrarily detained, or even killed."
(Additional reporting by Drazen Jorgic in Juba; Editing by Bernadette Baum)