"The seventh round [has] proved to be totally de-linked from what is going on in the field," Gemmo Lodesani, UN Deputy Humanitarian Coordinator for North Sudan, said.
Mediators had hoped that the latest talks between the Sudanese government and the two rebel groups, the Sudanese Liberation Army/Movement and the Justice and Equality Movement, which began in November, would yield a breakthrough that would end the three-year conflict in west Sudan.
"Out of three areas [under discussion in the Nigerian capital, Abuja] there is only one area that is moving - wealth sharing," he told IRIN in an interview.
"Security is the area that should have been tackled last year because if you have a logical sequence of discussion, there should be security, power sharing and wealth sharing," he added.
Lodesani also noted that the talks had not considered mounting tension between Sudan and neighbouring Chad which are blaming each other for cross-border incursions. Chadian president, Idriss Deby, has announced that he will not participate in the African Union summit in the Sudanese capital, Khartoum, next week.
The Abuja talks also ignored the very high level of insecurity in West Darfur State, he said, and the fact that Arab militias largely controlled West Darfur, but were not present at the talks.
"We are becoming very vocal because we have been trying to be conducive and understanding, [but] we cannot afford to continue like this," Lodesani said.
However, despite continuous insecurity throughout 2005, the UN deputy humanitarian coordinator noted that relief agencies had made substantial progress in Darfur, resulting in an improved food security situation and a reduction in the mortality rate.
"We are going to lose these gains and someone must be accountable," he said. "We cannot afford to have this type of joke on Darfur. [We need] at least [to] maintain what we had reached in 2005 - if it continues like this we are going to lose it."
Lodesani also drew attention to the ongoing insecurity in southern Sudan, which he said needed to be addressed urgently.
The Ugandan rebel group, the Lord's Resistance Army (LRA), for example, had increased its attacks in recent months, jeopardising the safety of civilians and aid workers in the region.
"There is a serious threat to security in the south. In my opinion, there is a need to beef up security," he noted.
Despite his concerns, however, he was sceptical about the widely held view that the LRA was responsible for all the recent security incidents.
"Actually, right now in the south, especially in [the region of] Equatoria, everything is LRA," he noted. "If a bandit or whatever is going to do something, it is LRA."
"I think we are doing the LRA a big favour because they come up as a super strong militia roaming over many millions of square miles from west to east," he added.
Nevertheless, the uncertainty of the exact strength of the LRA did not change the security concerns, Lodesani said: "The truth of the fact is that there is a lot of insecurity. Be it LRA or common banditry, the end result is the same."