The Sudanese Government has called on the United States to respond to the capture of a strategic southern Sudanese town.

Following the loss of Kapoeta to the Sudanese People's Liberation Army (SPLA) at the weekend, the Sudanese charge d'affaires in Kenya, Dirdiery Ahmed, told the BBC that the attack had broken a US-brokered ceasefire.

"The attack on Kapoeta is a flagrant violation of the agreement," he said.

The ceasefire was signed last December and is due to expire on 30 June.

Sudan says that Kapoeta was one of the areas covered to allow cattle vaccination - but the SPLA deny this.

Click here for more on the SPLA capture of Kapoeta

The Sudanese Government has itself hampered polio, guinea worm and rinderpest eradication programmes by refusing to authorise humanitarian planes to fly to certain areas, diplomats say.

Brass band

Sudan is lodging a complaint about the attack with the Bush administration.

The SPLA success is the result of 10 years of repeated offensives and was celebrated with a brass band playing amid the corpses of government soldiers killed during the fighting for the town.

The rebels deny breaking the ceasefire

SPLA commanders in Kapoeta told the BBC that 200 Sudanese soldiers were killed there and they talked of the possibility of capturing other southern towns like Torit and Juba.

But the Sudanese Government demands that the rebels "forego all of the military advantage which it has gained because of that illegal attack" and stop any further attacks in that part of the country.

Mr Ahmed told the BBC's Focus on Africa that the US-brokered agreement set up conflict-free zones and the SPLA took "undue advantage" of peace in the area to capture the town.

He did not say what Sudan would do if there was not a response to the Sudanese complaint but said government involvement in the peace talks due to take place in Kenya on 17 June would depend on the US response.