LEADERS of two quasi-official bodies from China and Taiwan are to sign an agreement on ways to upgrade cross-Strait ties at the end of an historic summit to be held in Singapore this month, it was jointly announced in Beijing yesterday. The statement was made by Mr Cheyne Chiu, secretary-general of Taiwan's Strait Exchange Foundation, and Mr Tang Shubei, vice-chairman of the mainland's Association for Relations Across the Taiwan Strait, after ending the first day of talks. According to official reports, Mr Tang said details of the ''mutually-recognised document'' including its contents and under what capacity the document would be issued would have to be further discussed. The Beijing talks will lay the groundwork for the so-called ''Wang-Koo talks'' between the association's chairman, Mr Wang Daohan and his opposite number, foundation chairman Mr Koo Chen-fu. The Singapore summit marks a significant step in the strengthening of contacts across the Strait in non-political areas, especially economic and anti-crime co-operation. Emerging after a two-hour session at the Diaoyutai state guesthouse, Mr Tang said yesterday's pre-summit boosted mutual understanding and created a sound basis for further discussion. He stressed that the two sides should strive to establish formal and regular channels to upgrade cross-Strait links. The two representatives are to sign two documents on ways of tracing lost mail and verifying travel documents at the end of another session tomorrow. The Singapore meeting will focus on ways to protect Taiwanese investment in the mainland and to co-operate in fighting crime. Mr Chiu, a former close aide of President Mr Lee Teng-hui, said both sides shared the view that there had been considerable protection for Taiwanese investment on the mainland. But more talks will have to be conducted on ways of giving further protection and ensure enforcement of the relevant laws. The China News Service quoted Mr Tang as saying both sides have had ''some common points'' as well as ''different points of emphasis'', adding that he was willing to solve the differences in a ''reasonable and appropriate'' way. ''I had a feeling that the distance between us could be shortened if we stand at a higher position,'' Mr Chiu said. Mr Tang agreed and called on the two sides to have a broader vision on mainland-Taiwan relations to help eliminate the differences and mutual distrust resulted from a lack of communication in the past four decades, he said. The New China News Agency said both sides have had preliminary talks on ways to encourage exchanges between youth groups, boost co-operation on labour importation, protection of copyrights, intellectual and property rights.