Soviet Foreign Minister Eduard Shevardnadze ended a historic visit to China Saturday with an agreement on the first Sino-Soviet summit in 30 years, but a top Chinese official contradicted him by saying its timing remains in dispute.

Shevardnadze told a news conference the summit between Chinese leader Deng Xiaoping and Soviet leader Mikhail Gorbachev would be held in mid-May and would represent the "complete normalization of relations between the Soviet Union and China."Ties between the two communist giants collapsed in the 1960s, but both have been working toward a thaw since 1982. Shevardnadze's four-day visit, including a Saturday morning meeting with Deng, was to set the stage for the summit, the final step toward normalizing relations.

The two nations agreed to the summit Friday, and Shevardnadze announced an agreement on the timing for the summit Saturday.

But minutes after Shevardnadze's plane took off for Pakistan, Chinese Deputy Foreign Minister Tian Zengpei contradicted him and told reporters further negotiations were needed to set a date.

The mid-May date "was a time frame proposed by the Soviet side," Tian told a news conference at Beijing airport. "But with regard to the specific timing of such a summit, it has yet to be decided.

"The Chinese side wishes to study the time frame proposed by the Soviet Union and is ready to have consultations with the Soviet side about the specific time," he said.

Tian's statements - including a refusal to declare the summit an indication full normalization of relations - left nagging questions about progress indicated earlier towards other issues such as a political settlement in Cambodia and border disputes.

Shevardnadze, confident and obviously pleased with his trip, told reporters earlier the summit was set for mid-May.

"The visit of Mikhail Gorbachev to the People's Republic of China will take place in mid-May of this year," Shevardnadze told reporters at a news conference delayed for two hours for undisclosed reasons.

"Let me emphasize that we are speaking of a complete normalization of relations," Shevardnadze said.

But Tian, who agreed normalization of relations would take place, said "I refuse to add on any adjectives."