UN Secretary-General Ban Ki-moon on Friday said that he is "deeply concerned" by the continued tension in the Abyei area, central Sudan, where more than 10 people were killed, and stressed that "the military stand-off is unacceptable."

A statement, issued here by Ban's spokesman, said, "The secretary-general calls upon the leadership of the National Congress Party (NCP) and Sudan People's Liberation Movement (SPLM) to refrain from any unilateral declarations regarding the ownership of the Abyei area as it jeopardizes the search for a peaceful resolution."

"The parties must refrain from provoking each other or engaging in any military confrontation in Abyei as this could result in further loss of life and significantly affect the future relationship between North and South," the statement said.

The United Nations has found 14 bodies in Sudan's oil-rich Abyei region, the apparent victims of the latest round of clashes in this disputed region of central Sudan, UN officials said on Tuesday.

The fighting broke out on Sunday when a Sudanese army officer insisted on entering the disputed territory after the police tried to stop his convoy of six landcruisers, reports said.

North and South have repeatedly accused each other of sending large numbers of "irregular" forces into Abyei, in violating a January truce which called for the withdrawal of all forces except policemen and United Nations peacekeepers.

Despite a referendum in January in which South Sudan voted to secede from the North, the status of Abyei remains unresolved.

The referendum marks the final phase of the 2005 Comprehensive Peace Agreement (CPA), which concluded 20 years of war between the northern-based government in Khartoum and the Sudan People's Liberation Movement/Army in the south.

Tensions have been high in Abyei for months as the area remains in dispute between the north and the south, which will formally separate in July.

"The secretary-general urges both sides to immediately implement the short-term containment measures as agreed in the Kadugli agreements of 13 and 17 January 2011 and the Abyei agreement of 4 March 2011, and to adhere to the timetable for their implementation," the statement said. "The resumption and conclusion of the negotiations on Abyei must now be a matter of priority."