Former United States State Department employee Kendall Myers and his wife, Gwendolyn, are arrested and charged with spying for Cuba's government.
- Former Cuban President Fidel Castro dismisses allegations that ex-U.S. State Department employee Kendall Myers spied for his country.
- The United States issues a health alert in China, following a government employee reporting "abnormal sensations of sound and pressure", one in a range of physical symptoms, from late 2017 through to April 2018. U.S. Secretary of State Mike Pompeo says the State Department is moving medical teams into place in Guangzhou, adding that the incident was "entirely consistent" with reported "sonic attacks" in Cuba in 2016 and 2017.
- The Trump administration, through the Department of State and Secretary of State Rex Tillerson, expels 15 Cuban diplomats, after pulling half of its own embassy staff from Havana on Sept. 29, due to the alleged failure of Cuba to take appropriate steps to protect American personnel against the mysterious health attacks.
- A senior European External Action Service official says that the European Union, in order to protect its companies doing business with Iran, could implement "blocking regulations" based on a legal framework set up in 1996 for E.U. trade with Cuba, should the United States pull out of the 2015 nuclear deal and restore its sanctions.
- The United States State Department orders Russia to close the Consulate-General in San Francisco and two other buildings by September 2, 2017, invoking "parity" over a Russian measure in July.