China is building its nuclear arsenal strictly for defensive purposes while the two superpowers wage the arms race to become "overlord of the world," a top military official said today.

The statement by Yu Qiuli, director of the Army's general political department, took pains to distinguish China's nuclear program from what he called the aggressive U.S. and Soviet designs.

"China is developing some nuclear and other sophisticated weapons, but the aim is to break down the nuclear monopoly and to guard against nuclear attack," he said in remarks released by the official news agency.

Although Yu merely restated Peking's position, his remarks are believed to be linked to the Aug. 11 visit of the International Atomic Energy Agency's director general.

Peking announced last week that the visit was arranged to discuss China's entry into the association, a U.N. body whose purpose is to develop peaceful uses of the atom and to prevent its diversion for military purposes. Diplomats said Yu's statement may have been intended to reconcile China's nuclear weapons program with the agency's objectives.

China exploded its first nuclear device in the 1960s and already has developed long-range intercontinental ballistic missiles capable of carrying nuclear warheads to any place in the Soviet Union and to the western United States. Yet Peking frequently criticizes Washington and Moscow for endangering world peace and calls on both superpowers to take the lead in disarmament.

When Moscow proposed last month that China join an international freeze on nuclear weapons, Peking replied that it would cut its atomic arsenal only after the superpowers reduced theirs by half.

"China emphasizes the development of regular weapons in accordance with the need to consolidate its national defense," said Yu, "while the superpowers have spent large sums of money on developing attack weapons, long-range weapons and their carriers."

Diplomats said Yu's remarks also may be a reply to recent criticism in the Mongolian Communist Party media, which protested Peking's rejection of the Soviet initiative.