4 September 2011 Last updated at 03:35 ET

Sudan: UN says thousands flee fighting in two states

By James Copnall BBC News, Khartoum

The opposition party fighting the Sudanese government is calling for a no-fly zone over two states.

The United Nation's refugee agency, UNHCR, says fighting has displaced thousands in Sudan's Blue Nile state.

Clashes broke out on Thursday night between the government and soldiers loyal to an opposition party with links to South Sudan.

The opposition party, SPLM North, is calling for a UN no-fly zone over Blue Nile, South Kordofan and Darfur.

In July South Sudan became independent, but Sudan is still fighting rebels in these states as well as Darfur.

A press release from SPLM-North also accuses the Sudanese armed forces of bombing and killing civilians in Blue Nile, and arresting hundreds of its party members.

The government spokesman for the armed forces was not immediately available for comment.

The government has control of Damazin, the state capital, and the rebels have largely retreated towards their base, Kurmuk, in the south of the state.

The UNHCR says it has received reports of 20,000 people fleeing across the border from Blue Nile into Ethiopia.

It has sent an assessment team to Western Ethiopia to find out more.

One resident of the capital of Blue Nile state, Damazin, said the town was almost deserted on Saturday afternoon, adding he could hear gunshots nearby.

Sudanese accusations

Most of the soldiers loyal to the opposition SPLM-North party have retreated to Kurmuk in the south of Blue Nile state.

They used to fight on the side of the rebels who recently won independence for South Sudan.

On Saturday the Sudanese Foreign Ministry announced the country was complaining to the UN Security Council about South Sudan's alleged role in supporting the SPLM-North fighters in Blue Nile.

It accused South Sudan's army of sending 25 armed land-cruisers to the state at the end of last month, for example.

Sudan had previously made a similar complaint about Southern Kordofan, where rebels loyal to SPLM-North have been fighting the government for the last three months.

South Sudan denies both charges.

The peace deal between Khartoum and the South Sudanese rebels signed in 2005 left three notable unresolved problems: the border regions of Abyei, Blue Nile and Southern Kordofan.

There has been heavy fighting in each one at some point in the last few months.