The United States, at a meeting tonight of the U.N. Security Council, called for an immediate ceasefire in Indochina and the withdrawal of Vietnamese forces from Cambodia along with that of Chinese troops from Vietnam.

The wars of Southeast Asia that have brought the danger of a clash between China and the Soviet Union have created an ominous situation, U.S. Ambassador Andrew Young told the Council.

"The United States has done everything possible to head off the dangers posed by the conflict," he said. "We have spoken out publicly and expressed our concerns directly to the Vietnamese, Soviet and Chinese governments about the dangers of continued, perhaps expanded fighting."

The Security Council meeting was convened only after backstage negotiations pushed by the United States reached agreement that the two invasions would be linked.

Even that linkage, however, left the Soviet Union displeased. The first resolution, submitted by the Soviet Union and Czechoslovakia, made no mention of Cambodia. It called for Chinese withdrawal from Vietnam and for U.N. members to halt all deliveries to China of arms or technology that could be used for military purposes. The resolution also demanded that China make retribution to Vietnam for damage caused in the fighting.

It seemed likely, according to informed sources, that the emergency council meeting would end with consideration of a resolution calling both for Chinese withdrawal from Vietnam and Vietnamese withdrawal from Cambodia, a resolution the Soviets would likely veto. Such a veto would come Saturday evening at the earliest. The meeting adjourned tonight without action.

The Chinese would abstain on such a resolution, according to informed sources, because of their announced intention to withdraw eventually from Vietnam. Vietnam has expressed no intention of withdrawing from Cambodia and the Soviet Union energetically supports Vietnam's interests.

U.N. Secretary General Kurt Waldheim and other diplomats are working, however, to find a way to involve the United Nations in efforts to restore peace in Southeast Asia. Waldheim today called the present situation the most serious threat to world peace since the Cuban missile crisis of 1962. He was reported to be considering an attempt to convene a new international conference on Indochina like the one held in Geneva in 1954.

In addition to a troop withdrawal following immediate cease-fires in Vietnam and Cambodia, Young urged the Security Council to call for international efforts "perhaps under the auspices of the secretary general" to end the Indochina fighting. He noted that Waldheim has offered to travel to the area.

Young called the U.S. position "objective" and said China has no more right to invade Vietnam than Vietnam had to overrun Cambodia.

"These actions have wide and dangerous implications for the peace of Asia," he said.

The Security Council meeting opened with a clash between China and the Soviet Union over the agenda linking the two Southeast Asian invasions.

Soviet delegate Mikhail Kharlamov said the United Nations should deal exclusively with Peking's "flagrant aggression," which he said was a part of Chinese expansionist plans in Southeast Asia. He told the Council that China seeks to impose "Maoist tyranny" like the "Pol Pot tyranny" of the Cambodian regime, overthrown by Vietnamese military action.

Chinese delegate Chen Chu argued that the Cambodian situation should be considered first. He called the present Cambodian government "national scums" who are puppets of Vietnam.

Kharlamov quoted Vietnamese reports of Chinese incursions into Vietnam prior to the large-scale invasion. Chen read a long list of dates and places at which he said Vietnamese forces had provoked China with border incidents.

Chen described China's invasion as "a just action" launched in selfdefense.

China, he said, is prepared to enter into peace negotiations with Vietnam at a mutually agreed place.