Trump’s threats of secondary tariffs are “never going to go anywhere” as long as he is unwilling to impose costs on Moscow directly, Keir Giles, a senior fellow at the London-based Chatham House think tank, told NBC News Monday.

European Union officials have drawn up plans to impose levies on American imports, but questions abound about whether they would go through with them.

President Donald Trump said he's “disappointed but not done” with Russian President Vladimir Putin, following an announcement of renewed military support for Ukraine and a plan to target buyers of Russian oil with tariffs up to 100% if a deal to end the war isn’t reached within 50 days.