The Russian leader is convinced that Moscow’s battlefield superiority is growing, and that Ukraine’s defenses may collapse in the coming months, according to people close to the Kremlin.

United States President Donald Trump accused his Russian counterpart Vladimir Putin on Tuesday of talking “bulls***” about Ukraine, saying the US would send Ukraine more weapons to defend itself. Trump’s expletive reflected his growing frustration with the Kremlin leader over the grinding war that Moscow launched more than three years ago.

Trump’s decision to help Ukraine fight an onslaught of Russian attacks reverses a Pentagon decision to withhold defensive weapons.