Sanctions and embargoes

In this Wednesday, July 3, 2019 photo, Iranian musicians play while performing 19th century Russian composers in Tehran Symphony Orchestra at Unity Hall, in Tehran, Iran. (AP Photo/Vahid Salemi)

President Donald Trump talks during a signing ceremony in the Oval Office of the White House in Washington, Monday, July 1, 2019, with Vice President Mike Pence, left, and Secretary of Health and Human Services Alex Azar. The president signed a $4.6 billion aid package to help the federal government cope with the surge of Central American immigrants at the U.S.-Mexico border. (AP Photo/Carolyn Kaster)

In this Monday, June 10, 2019 photo, Iranian Foreign Minister Mohammad Javad Zarif speaks during a press conference with his German counterpart Heiko Maas after their talks in Tehran, Iran. Zarif acknowledged Monday, July 1, 2019, Iran had broken the limit set on its stockpile of low-enriched uranium by the 2015 nuclear deal, marking its first major departure from the unraveling agreement a year after the U.S. unilaterally withdrew from the accord. (AP Photo/Ebrahim Noroozi)

People watch a TV screen showing the U.S. President Donald Trump, center, North Korean leader Kim Jong Un and South Korean President Moon Jae-in, center right, at the border villages of Panmunjom, at the Seoul Railway Station in Seoul, South Korea, Sunday, June 30, 2019. (AP Photo/Ahn Young-joon)

U.S. Special Representative for North Korea Stephen Biegun sits during a meeting with South Korea's Special Representative for Korean Peninsula Peace and Security Affairs Lee Do-hoon at Foreign Ministry in Seoul, South Korea, Friday, June 28, 2019. Biegun arrived Thursday for a four-day visit ahead of U.S. President Donald Trump's scheduled visit to Seoul. (AP Photo/Lee Jin-man, Pool)

Brian Hook , the U.S. special envoy for Iran, gestures during an interview in Paris, Thursday, June 27, 2019. Brian Hook is meeting with top French, German and British diplomats in Paris for talks on the Persian Gulf crisis at a time when European powers are trying to save the 2015 nuclear deal with Tehran. (AP Photo/Nicolas Garriga)

In this Wednesday, June 26, 2019, photo, South Korean Unification Minister Kim Yeon-chul listens to a question during a group interview at a hotel in Seoul, South Korea. The U.S. and North Korea both feel the need to resume diplomacy and are trying to narrow their differences for new summit talks, Kim said as he contrasted their efforts with the tensions surrounding Iran's collapsing nuclear accord. (AP Photo/Ahn Young-joon)

Acting U.S. Secretary for Defense Mark Esper, right, greets Turkish Defense Minister Hulusi Akar prior to a meeting of NATO defense ministers at NATO headquarters in Brussels, Wednesday, June 26, 2019. (AP Photo/Virginia Mayo, Pool)

In this undated file photo provided on Sunday, June 23, 2019, by the North Korean government, North Korean leader Kim Jong Un reads a letter from U.S. President Donald Trump. South Korea's President Moon Jae-in on Tuesday, June 25, 2019, said North Korean and U.S. officials are holding "behind-the-scenes talks" to set up a third summit between the countries' leaders. 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, File)

U.S. National Security Advisor John Bolton gives statements to media in Jerusalem, Sunday, June 23, 2019. (AP Photo/Tsafrir Abayov, Pool)