US President Donald Trump has announced the US will send "top-of-the-line weapons" to Ukraine via Nato countries, while also threatening Russia with severe tariffs if a deal to end the war is not reached within 50 days.

President Trump has long boasted of his friendly relationship with Putin, and after taking office in January repeatedly said that Russia was more willing than Ukraine to reach a peace deal.

Trump said the United States would put 100% secondary tariffs on countries that do business with Russia if a deal if a peace deal is not reached in 50 days.