The top UN envoy to Sudan has warned that difficulties remain in fully carrying out a peace accord signed in 2005 despite the progress in healing the strife-torn country's divides, the United Nations said Thursday.

Many challenges face the signatories to the Comprehensive Peace Agreement (CPA) that ended a 21-year civil war between northern and southern Sudan, said Ashraf Qazi, the UN secretary-general's special representative, on Wednesday after a meeting with Sudanese First Vice President Salva Kiir Mayardit, according to a UN news release.

Qazi, who also heads the UN Mission in Sudan (UNMIS), made the remarks ahead of a meeting in the United States on the Sudan issue scheduled for late June.

"I had a very good meeting with the president and this is an important time because we all are preparing for the conference that will take place in Washington later this month," he said during a one-day visit to Juba, capital of Southern Sudan.

"The United States has taken the initiative to act in concert with the international community to help both signatories implement the CPA on schedule because the CPA time period will be completed in 2011," Qazi added.

At the meeting, they discussed the security situation in Southern Sudan, elections, the disarmament, demobilization and reintegration program for ex-militants, and the preparations for the 2011 referendum on whether Southern Sudan should secede or remain united with the rest of the country.

Mayardit, who is also president of the Government of Southern Sudan, expressed appreciation for the role of UNMIS, which recently dispatched some 120 civilian, military and police personnel to Jonglei state, where thousands were taking refuge after inter-tribal violence left hundreds dead, including many women and children.

Source:Xinhua