The Greek and Turkish Cypriot leaders are expected to hold their last meeting of the fourth round of talks on Tuesday, with United Nations Secretary-General Kofi Annan’s special adviser on Cyprus, Alvaro de Soto, scheduled to be on hand, the UN announced on Monday.

According to the UN statement issues on Monday by Mr. de Soto, 'although the Greek Cypriot leader, H.E. Glafcos Clerides, and the Turkish Cypriot leader, H.E. Rauf Denktash, will be meeting in Cyprus, the goal of resolving the core issues has eluded the negotiators in the fourth round."

“This is regrettable," he stated "for such a breakthrough by the end of June would have greatly facilitated the detailed legal drafting of a comprehensive settlement which must to be completed in the autumn of this year if the unique opportunity that is now open is to be seized."

The Special Adviser said that “it has become all the more necessary that when the talks resume all concerned show the necessary political determination and willingness to compromise that are required for a decisive move forward in the summer.”

UN spokesman Fred Eckhard said that Mr. de Soto would leave Cyprus to meet the Secretary-General Wednesday in Vienna, adding that the Special Adviser will brief the Security Council at UN Headquarters next week.

Talks between the two Cypriot leaders are to resume after Mr. de Soto’s return from New York, the spokesman said.