South Sudan military forces tasked with carrying out a disarmament campaign among feuding ethnic groups are raping, torturing and killing members of a minority community, community leaders and aid workers say.

The disarmament campaign follows two outbreaks of violence linked to cattle raids between the Murle and Lou Nuer tribes over the last year in the remote state of Jonglei. Hundreds — and likely more than 1,000 — people were killed in the two clashes.

In an effort to stem future violence, the Sudan People's Liberation Army, South Sudan's military, embarked on a disarmament campaign in March in which more than 10,000 weapons have been taken so far, said military spokesman Col. Philip Aguer.

But aid groups and community members say the SPLA is killing and torturing members of the Murle, a tribe reviled by many other South Sudanese, while carrying out the disarmament campaign. Alleged abuses include simulated drownings, tying up young men to trees and beating them, and widespread rape against women.

The Murle appear to be ostracized by most other tribes in South Sudan in part because they received military support from leaders in Khartoum, Sudan, when the south and north battled in a two-decade civil war. The Murle also have a reputation for carrying out child abductions from other tribes and of conducting cattle raids that can results in hundreds of human deaths and tens of thousands of stolen cattle.

Allegations of abuse during the disarmament campaign are being investigated by military lawyers, Aguer said.

A state government report dated March 30 and obtained by The Associated Press listed some of the deaths: James Kengen Logidang was killed at home while sitting in a chair. Korok Manyngar Kengen, 15, was killed as his cattle were being stolen by SPLA soldiers. "The boy didn't have a gun," the report said.

The aid group Medecins Sans Frontieres, or Doctors Without Borders, said it has treated 30 patients since mid-March who suffered injuries from the disarmament campaign. Two have since died. Three patients had gunshot wounds and 26 had trauma injuries from beatings, the group said.

Aid groups contend that such numbers are underreported because most of the attacks take place in remote areas.

The disarmament campaign began as a voluntary handing over of guns, and then was to move into a compulsory phase, though military leaders have since said the voluntary phase would continue. Aid groups question whether the process is truly voluntary.

Peter Guzulu, a member of the Murle community, said at least 10 people have been killed "for no apparent reason." An 11th death took place against a male running from soldiers with a rifle in hand, he said.

Guzulu was the chairman of the government-run Jonglei Human Rights Commission from September 2010 until mid-March, when he said he was dismissed by the governor but wasn't told why. Guzulu believes he was removed "so I didn't talk to journalists or write reports."

"People are being beat in the towns and villages. They are told to confess to having guns. Women are beaten. Some are raped. When is this torture going to end? That is the question people ask all the time," he said.

Aguer said all communities in Jonglei are being disarmed. He said the Murle have the most weapons and that some members are heading into Ethiopia to keep their AK-47 assault rifles.

A report published last month by five aid groups, including Washington D.C.-based Pact and the South Sudan Law Society, said the current disarmament campaign — the fifth in Jonglei in the last six years — risks perpetuating a cycle of violence that has seen thousands killed and hundreds of thousands displaced in recent years. If the Murle believe they are being forcibly targeted in the campaign, the report said, they will re-arm and seek revenge.

The report urges the U.N. to prioritize the protection of civilians.

A statement this month from the U.N.'s top representative in South Sudan, Hilde Johnson, commended the disarmament effort, but critics of the campaign say the U.N. mission in South Sudan is ignoring evidence of abuse and torture.

The U.N. said in April that a peaceful disarmament campaign that respects human rights is vital to ending the cyclical violence and noted that while cases of abuse and sexual violence have been reported they do not appear to be part of a systematic campaign.

Kouider Zerrouk, a spokesman for the U.N. mission, said the U.N. has no way of knowing how many cases of abuse have occurred.

"These human rights violations are serious and are a concern for us," Zerrouk said. "But if we look into the whole process covering the whole region as big as Bangladesh, yes, generally it went in a peaceful manner in the sense that there was no outbreak of major clashes between communities."

Aguer said the disarmament campaign would continue for the rest of the year.

Judy McCallum, the former head in South Sudan of the aid group Pact, said the Murle are "basically under siege" by the government and military. She added that Murle youth are "out of control" — a reference to cattle-raiding attacks — but have no path to improve their lives.

Aid groups, McCallum said, are reporting systemic rape and drownsings. "Everyone I talk to say women are being raped constantly. So there's no incentive to give up their guns," she said. She said there is impunity for violence against the Murle.

McCallum said the U.N. is overemphasizing the success of the disarmament campaign and does not appear to be adequately concerned with the protection of civilians.

Minority Rights Group International on Thursday released new rankings of peoples under threat. South Sudan — which broke away from Sudan last year to become the world's newest nation — ranked in the top 10 because of the Murle-Lou Nuer violence.

In December and January, members of the Lou Nuer community attacked the Murle, likely killing hundreds of people. That attack came in retaliation for an August attack by the Murle that killed at least 600.