The United States has long asked Ukraine not to use US-provided military equipment to carry out attacks inside Russian territory, the top US general said on Thursday, following accusations pro-Ukrainian militia used US armored vehicles.

Army General Mark Milley, chairman of the Joint Chiefs of Staff, said his office was looking into imagery showing the vehicles allegedly used in an attack the Russian border region of Belgorod. But he said the US position against such US equipment being used inside Russia was clear to Kyiv.