Amnesty International has said the UN Security Council must do more to protect civilians in Sudan and take immediate action to halt the military’s indiscriminate air strikes.
In a report released on Thursday, the UK-based rights group called for aid organisations to be granted immediate access to affected areas in Southern Kordofan and Blue Nile state.
Violence in the area broke out a year ago, primarily over oil. More than 500,000 people have since been displaced by fighting and food shortages.
Fighting in South Kordofan first erupted in June last year between the Sudanese military and the Sudan Peoples Liberation Movement-North (SPLM-N), an armed opposition group aligned with forces in South Sudan.
The conflict then spread to Blue Nile state. Both states neighbour South Sudan, which seceded from Sudan in July.
"The situation is desperate and time is running out to ensure the refugees have adequate protection and supplies during the six-month rainy season," Khairunissa Dhala, Amnesty International’s South Sudan researcher, said.
Amnesty said its researchers visited eight refugee camps in South Sudan in March and April 2012, where inhabitants faced risks such as forced recruitment into armed groups and sexual violence, in addition to food and water shortages.
In refugee camps in Upper Nile State, the organisation received reports of boys and young men being forcefully recruited into the SPLM-N.
'Not done enough'
Scott Edwards, from Amnesty's Advocacy, Policy and Research department, told Al Jazeera the international community had done little to improve the situation on the ground.
"They [the Security Council] have had months, knowing the full extent of the crimes occurring in South Kordofan," he said.
"They've done very little. They've not condemned indiscriminate bombing. They've not done enough to extend the arms embargo which currently covers Darfur."
Amnesty wants the Security Council to expand the current UN arms embargo on the western Darfur region to cover the whole of Sudan, in order to stop the flow of weapons.
The UN says more than 114,000 people fled to South Sudan from South Kordofan and Blue Nile state between June 2011 and April 2012. Many more have been internally displaced.
Thousands of displaced villagers in South Kordofan have fled to the mountains and are sheltering in caves.
In March, Al Jazeera gained access to the remote region and documented evidence of villages and crops having been destroyed.