Serbian President Aleksandar Vucic speaks during a news conference with Slovakia's Prime Minister Robert Fico in the Serbia Palace in Belgrade, Serbia, Thursday, Nov. 21, 2024. (AP Photo/Darko Vojinovic)

FILE - A worker is seen in the NIS Jugopetrol oil refinery, prior to a visit by Russian deputy prime minister Dmitry Medvedev, in Pancevo, some 16 kilometers (10 miles) north of Belgrade, Serbia, Monday, Feb. 25, 2008.(AP Photo/Darko Vojinovic, File)

FILE - A view of NIS Jugopetrol oil refinery in Pancevo, Serbia, on Dec. 24, 2008. (AP Photo/Darko Vojinovic, File)