Defense Secretary Frank Carlucci said Friday the United States and Vietnam have agreed to begin joint efforts Sept. 25 to locate U.S. military personnel, dead or alive, in Vietnam.

Last month, Vietnam suspended its offer to conduct joint operations, but Carlucci, speaking at POW-MIA Recognition Day ceremonies on the steps of the Capitol, said the Vietnamese "recently agreed to resume cooperation.""I am pleased to announce that joint activity will begin on Sept. 25," Carlucci said.

Carlucci, joined by several members of Congress, stressed that resolving the prisoners of war-missing in action issue is a bipartisan quest and supported by all Americans.

Noting there still are 2,393 Americans who served in the Vietnam War "about whom we do not have final answers," Carlucci reminded the audience that President Reagan has said "that resolving the fate of these Americans is a matter of highest national priority."

"I can assure all Americans the Department of Defense is committed to doing everything possible to resolving the POW-MIA issue successfully. Today we are encouraged in our quest, but we still await the results that we know are possible from those who hold the answers," he said.

Carlucci cited Vietnam's recent announcement that it will withdraw its forces from Cambodia and said that move should coincide with greater efforts to resolve the U.S. POW-MIA question.

He urged the government in Hanoi "to resolve this issue; to resolve it quickly; to resolve it this year. Let us also repeat the president's call for Cambodia to agree to our proposal to repatriate the remains that they claim to hold," Carlucci said. He also reported that last month "we held encouraging consultations" with the government of Laos "and agreed to conduct joint surveys commencing soon and to meet thereafter to plan subsequent excavations and further joint efforts."

"We are sending a message to the world community that America has unshakably resolved to see that any Americans still held captive are returned and that all recoverable remains will be laid to rest in their native land," Carlucci said.