KADUGLI (AFP) - A heavily armed Sudanese military convoy entered the flashpoint border district of Abyei, sparking clashes that left up to 14 people dead, its chief administrator and a UN spokesman said on Tuesday. The fighting broke out on Sunday when a Sudanese army major insisted on entering the disputed territory after the police tried to stop his convoy of six landcruisers mounted with machine guns and more than 200 troops, administrator Deng Arop Kuol told AFP. "They killed a local police sergeant from the SPLA (Sudan People's Liberation Army -- the southern armed forces). I think the UN recovered another 11 bodies. It was a violent clash," said the southern-nominated official. A UN spokesman confirmed the deadly clashes on Sunday, saying a peacekeeping patrol had found 14 bodies, after initially being denied access to the area by an angry crowd. "One of our patrols went to the scene of the fighting on Monday, where they found 14 dead bodies, 11 of them in JIU uniform and three in civilian clothes," said Kouider Zerrouk, referring to the special Joint Integrated Units of northern and southern personnel deployed in Abyei. The district's chief administrator said the army had been trying to supply northern elements of the joint units with extra weapons and described their presence in Abyei as "illegal." "They were not supposed to enter our territory according to the Abyei protocol. So there was a plan of invading," Kuol said, referring to an annexe of the 2005 peace deal that ended a devastating 22-year civil war between north and south. Kuol said that northern elements of the joint units set up under the protocol had joined the fighting, which took place around 17 kilometres (10 miles) north of Abyei town. He said the northern troops were now in Goli -- further north but still within the district's boundaries. The Sudanese army spokesman was not immediately available to comment on the allegations. North and south have repeatedly accused each other of sending large numbers of "irregular" soldiers into Abyei, in breach of a January truce which called for the withdrawal of all forces except the JIUs and UN peacekeepers. Deadly fighting and recriminations have flared in Abyei since January, when the district had been due to vote on its future, alongside a referendum in the south that delivered a landslide for secession. The plebiscite was postponed indefinitely amid deadlock between north and south over who should be eligible to vote. The United Nations and Western observers have reported that the armies on both sides have been reinforcing their positions in recent months, raising fears of the violence escalating. Abyei's future is the most sensitive of a raft of issues which the two sides are struggling to reach agreement on ahead of international recognition of southern independence in July.