Nuclear weapons

In this photo provided by the North Korean government, North Korean leader Kim Jong Un speaks at the ruling party congress in Pyongyang, North Korean, Friday, Jan. 8, 2021. Kim threatened to expand his nuclear arsenal and develop more sophisticated weapons systems, saying the fate of relations with the United States depends on whether it abandons its hostile policy, state media reported Saturday. The congress, the Workers Party's top decision-making body, convened for the first time in five years. Independent journalists were not given access to cover the event depicted in this image distributed by the North Korean government. The content of this image is as provided and cannot be independently verified. Korean language watermark on image as provided by source reads: "KCNA" which is the abbreviation for Korean Central News Agency. (Korean Central News Agency/Korea News Service via AP)

A Marine stands outside the entrance to the West Wing of the White House, signifying President Donald Trump is in the Oval Office, Thursday, Jan. 7, 2021, in Washington. (AP Photo/Patrick Semansky)

In this photo provided by the North Korean government, North Korean leader Kim Jong Un attends a ruling party congress in Pyongyang, North Korea Tuesday, Jan. 5, 2021. Kim opened its first Workers’ Party Congress in five years with an admission of policy failures and a vow to lay out new developmental goals, state media reported Wednesday. Independent journalists were not given access to cover the event depicted in this image distributed by the North Korean government. The content of this image is as provided and cannot be independently verified. Korean language watermark on image as provided by source reads: "KCNA" which is the abbreviation for Korean Central News Agency. (Korean Central News Agency/Korea News Service via AP)

In this photo released Monday, Jan. 4, 2021, by Tasnim News Agency, a seized South Korean-flagged tanker is escorted by Iranian Revolutionary Guard boats on the Persian Gulf. Iranian state television acknowledged that Tehran seized the oil tanker in the Strait of Hormuz. The report on Monday alleged the MT Hankuk Chemi had been stopped by Iranian authorities over alleged “oil pollution” in the Persian Gulf and the strait. (Tasnim News Agency via AP)

FILE - This Nov. 4, 2020, file satellite photo by Maxar Technologies shows Iran's Fordo nuclear site. Iran has told international nuclear inspectors it plans to enrich uranium up to 20% at its underground Fordo nuclear facility, a technical step away from weapons-grade levels, as it increases pressure on the West over its tattered atomic deal. (Maxar Technologies via AP, File)

In this photo released by the official website of the Iranian Defense Ministry, military military commanders attend a funeral ceremony of Mohsen Fakhrizadeh, a scientist who was killed on Friday, in a funeral ceremony in Tehran, Iran, Monday, Nov. 30, 2020. Iran held the funeral Monday for the slain scientist who founded its military nuclear program two decades ago, with the Islamic Republic's defense minister vowing to continue the man's work "with more speed and more power." (Iranian Defense Ministry via AP)

In this photo released by the official website of the Iranian Defense Ministry, military personnel carry the flag draped coffin of Mohsen Fakhrizadeh, a scientist who was killed on Friday, in a funeral ceremony in Tehran, Iran, Monday, Nov. 30, 2020. Iran held the funeral service for Fakhrizadeh, who founded its military nuclear program two decades ago, with the Islamic Republic's defense minister vowing to continue the man's work "with more speed and more power." (Iranian Defense Ministry via AP)

In this picture released by the Iranian Defense Ministry and taken on Saturday, Nov. 28, 2020, people pray over the flag draped coffin of Mohsen Fakhrizadeh, an Iranian scientist linked to the country's disbanded military nuclear program, who was killed on Friday, during a funeral ceremony at the Imam Reza holy shrine in the northeastern city of Mashhad, Iran. An opinion piece published by a hard-line Iranian newspaper has suggested that Iran must attack the Israeli port city of Haifa if Israel carried out the killing of a scientist. (Iranian Defense Ministry via AP)

This photo released by the semi-official Fars News Agency shows the scene where Mohsen Fakhrizadeh was killed in Absard, a small city just east of the capital, Tehran, Iran, Friday, Nov. 27, 2020. Fakhrizadeh, an Iranian scientist that Israel alleged led the Islamic Republic's military nuclear program until its disbanding in the early 2000s was “assassinated” Friday, state television said. (Fars News Agency via AP)