US Secretary of State Antony Blinken (L) and his Ukrainian counterpart Dmytro Kuleba shake hands prior their talks in Kyiv, on May 14, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken (L) and his Ukrainian counterpart Dmytro Kuleba shake hands prior their talks in Kyiv, on May 14, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken (L) and his Ukrainian counterpart Dmytro Kuleba shake hands prior their talks in Kyiv, on May 14, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken (L) and his Ukrainian counterpart Dmytro Kuleba shake hands prior their talks in Kyiv, on May 14, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken (L) and his Ukrainian counterpart Dmytro Kuleba walk for the start of their talks in Kyiv, on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken (L) and his Ukrainian counterpart Dmytro Kuleba walk for the start of their talks in Kyiv, on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken (R) and his Ukrainian counterpart Dmytro Kuleba holds a bunch of flowers each as they walk along the Memory Wall of Fallen Defenders of Ukraine in the Russian-Ukrainian War, in Kyiv on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken (R) listens to his Ukrainian counterpart Dmytro Kuleba as they walk along the Memory Wall of Fallen Defenders of Ukraine in the Russian-Ukrainian War, in Kyiv on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken (R) and his Ukrainian counterpart Dmytro Kuleba holds a bunch of flowers each as they walk along the Memory Wall of Fallen Defenders of Ukraine in the Russian-Ukrainian War, in Kyiv on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken (R) and his Ukrainian counterpart Dmytro Kuleba hold a bunch of flowers each as they walk along the Memory Wall of Fallen Defenders of Ukraine in the Russian-Ukrainian War, in Kyiv on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken (R) and his Ukrainian counterpart Dmytro Kuleba lay flowers along the Memory Wall of Fallen Defenders of Ukraine in the Russian-Ukrainian War, in Kyiv on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken (R) and his Ukrainian counterpart Dmytro Kuleba hold a bunch of flowers each as they walk along the Memory Wall of Fallen Defenders of Ukraine in the Russian-Ukrainian War, in Kyiv on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken (R) and his Ukrainian counterpart Dmytro Kuleba look at the portraits on the Memory Wall of Fallen Defenders of Ukraine in the Russian-Ukrainian War, in Kyiv, on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken (R) listens to his Ukrainian counterpart Dmytro Kuleba as they look at portraits decorating the Memory Wall of Fallen Defenders of Ukraine in the Russian-Ukrainian War, in Kyiv on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken holds a 3D-printed eagle during his visit to the Brave1 facility, in Kyiv on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Courtney McBride / AFP)

US Secretary of State Antony Blinken (R) and his Ukrainian counterpart Dmytro Kuleba lay flowers along the Memory Wall of Fallen Defenders of Ukraine in the Russian-Ukrainian War, in Kyiv on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken holds a 3D-printed eagle during his visit to the Brave1 facility, in Kyiv on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Courtney McBride / AFP)

US Secretary of State Antony Blinken (R) and his Ukrainian counterpart Dmytro Kuleba walk past St. Michael's Golden-Domed Monastery frescos in Kyiv, on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken (R) and his Ukrainian counterpart Dmytro Kuleba walk past St. Michael's Golden-Domed Monastery frescos in Kyiv, on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)

US Secretary of State Antony Blinken (R) listens to his Ukrainian counterpart Dmytro Kuleba (C) as they walk past St. Michael's Golden-Domed Monastery, in Kyiv on May 15, 2024. The United States will back Ukraine until its security is "guaranteed", US Secretary of State Antony Blinken said on a trip to Kyiv on May 14, 2024, hours after Russian forces claimed further advances in the northeastern Kharkiv region. (Photo by Sergei SUPINSKY / AFP)