SARAJEVO, Bosnia-Herzegovina (AP) — Bosnia has received 10,000 vaccines from neighboring Serbia amid a dispute with the international COVAX mechanism over a delay in planned shipments. The Balkan nation has threatened to sue the program unless the vaccines arrive as agreed. Bosnia has asked for 1.2 million vaccines that would cover about one third of its population. Serbia’s populist president, Aleksandar Vucic, flew to the Bosnian capital of Sarajevo on Tuesday to deliver the shipment of AstraZeneca vaccines to the authorities there. Vucic described the move as an act of solidarity and urged closer cooperation among the Balkan countries.