New York - The comprehensive peace agreement between the Sudanese government and southern Sudan would unravel unless the two sides take steps to implement it, UN Secretary General Ban Ki-moon said Thursday in an progress report.

The 2005 agreement ended a decades-long civil war between the Muslim-led Khartoum government and Christian groups in the south, with the inclusion of southern leaders in the Khartoum government. But key benchmarks in the deal remain unfulfilled, including north- south border demarcation, disarmament and census.

Ban said in the report to the United Nations Security Council that those benchmarks should be met before a scheduled referendum in 2011.

"With little over two years of the interim period remaining, the comprehensive peace agreement has reached a critical juncture where any action or inaction on its provisions will have a profound impact on the future of Sudan," Ban said.

He said southern Sudan's self determination, an issue in the agreement, is complex and will have a great impact on Sudan's security and stability.

"The parties to the agreement are yet to present a convincing case for unity to the people of southern Sudan," he said, urging the south to explore "all options" available to make unity a possibility in the peace process.

The report said insecurity continues to plague parts of Sudan. A 10,000-strong UN peacekeeping operation has been deployed to monitor the north-south peace agreement.

Another issue that may bring instability is the indictment of Sudanese President Omar al-Bashir by the International Criminal Court (ICC) of war crimes and crimes against humanity in the ethnic conflict in Darfur. The ICC at The Hague may issue a warrant to arrest al-Bashir and Khartoum has already warned of retaliation against the UN.

"The ICC's actions have a major impact on Sudanese political dynamics and have diverted much attention at a time when oustanding issues related to the (north-south) peace agreement require the parties' cooperation and renewed commitment," the report said.

The ICC has been investigating crimes in Darfur as well in other parts of Sudan. (dpa)