Donald Trump has said he believes Ukraine can win back all of the territory Russia has taken since its invasion. Volodymyr Zelensky and Donald Trump held a meeting at the United Nations | GETTYIn his post on Tuesday, however, Mr Trump hinted at stronger action. "Putin and Russia are in BIG Economic trouble, and this is the time for Ukraine to act," the post said. Mr Zelensky said he had discussed Russia's stuttering economy during a meeting with Mr Trump that he said was constructive. Asked whether Nato countries should shoot down Russian aircraft that enter their airspace, Mr Trump told reporters: "Yes, I do."