Nuclear weapons

Kim You-geun, deputy director of South Korea's presidential national security office, speaks at the presidential Blue House in Seoul, South Korea, Friday, Nov. 22, 2019. South Korea says it has decided to continue a 2016 military intelligence-sharing agreement with Japan it previously decided to terminate amid ongoing disputes over their wartime history and trade. (AP Photo/Ahn Young-joon)

U.S. Defense Secretary Mark Esper, left, and Vietnamese Defense Minister Ngo Xuan Lich talk before a meeting in Hanoi, Vietnam Wednesday, Nov. 20, 2019. Esper is on a visit to Vietnam to strengthen the military relations with the Southeast Asian nation. (AP Photo/Hau Dinh)

In this Nov. 16, 2019, photo, Japanese Archbishop Mitsuaki Takami, who heads Nagasaki's Catholic community of 60,000, the biggest in Japan, speaks in front of a statue of the Virgin Mary that was damaged in the A-bomb attack, at the Urakami Cathedral in Nagasaki, southern Japan. Pope Francis will start his first official visit to Japan in Nagasaki, ground zero for the Christian experience in a nation where the Catholic leader once dreamed of living as a missionary. (AP Photo/Eugene Hoshiko)

FILE - In this Nov., 20, 2013, file photo, radioactive waste, sealed in large stainless steel canisters, are stored under five-feet of concrete in a storage building at the Savannah River Site near Aiken, S.C. The federal government is arguing that it has already promised no more weapons-grade plutonium will be sent to Nevada, and the state lacks standing to seek a court order to force the Energy Department to remove it. Documents filed late Friday, Nov. 15, 2019 in U.S. District Court in Reno brand as "conjectural" or "hypothetical" state complaints that residents are harmed by radiation from material secretly trucked a year ago from South Carolina to Nevada. (AP Photo/Stephen B. Morton, File)

U.S. Defense Secretary Mark Esper, right, and South Korea defense Minister Jeong Kyeong-doo attend a press conference in Bangkok, Thailand, Sunday, Nov. 17, 2019. Esper and his South Korean counterpart announced Sunday that U.S. and South Korea are postponing a joint military air exercise that North Korea has criticized as provocative. (AP Photo/Robert Burns)

FILE - This May 6, 2013 file photo shows a wind turbine farm owned by PacifiCorp near Glenrock, Wyo. The military wants North Dakota and perhaps four other states with nuclear missile arsenals to consider new rules aimed at preventing conflicts between wind turbines and helicopters that provide security at launch facilities. Defense Department and Air Force officials were meeting Tuesday, Oct. 29, 2019 with North Dakota lawmakers and regulatory officials. (AP Photo/Matt Young, File)

FILE- In this Dec. 15, 2015, file photo, A U. S. Air Force F-15 fighter jet takes off from Incirlik Air Base near Adana, Turkey. Frayed U.S. relations with Turkey are raising a sensitive question rarely discussed in public: Should the United States remove the nuclear bombs it keeps at a Turkish air base? There is no known evidence that the weapons are at direct risk, but President Donald Trump has threatened to “obliterate” Turkey’s economy if it does not halt its invasion of Syria, and some American arms control experts say the bombs would be safer elsewhere. (AP Photo)

Russian President Vladimir Putin attends a meeting at the Russian Defense Ministry in Moscow, Russia, Thursday, Oct. 17, 2019. (Alexei Druzhinin, Sputnik, Kremlin Pool Photo via AP)

In this Oct. 5, 2019 FILE photo, North Korean negotiator, Kim Miyong Gil speaks outside the North Korean Embassy in Stockholm, Sweden, Saturday, Oct. 5, 2019. North Korea is calling an outside condemnation of its weapons launches a "grave provocation" and threatening to resume nuclear and long-range missile tests. (Yonhap/Pool photo via AP, File)