Donald Trump’s threat to impose secondary sanctions on countries buying Russian oil is probably more symbolic than practical, leading oil analyst and senior fellow at the Carnegie Russia Eurasia Center,

Shares of energy companies fell alongside oil futures as the likelihood of rate cuts and of U.S. sanctions on Russia in the near term shrank.

According to the International Energy Agency, Russia's revenue from sales of crude oil and oil products in June declined by almost 14% from a year earlier to $13.57 billion.

The president also threatened new measures to increase economic pressure on Russia as he grows more frustrated with Putin.

Now President Donald Trump is betting that his go-to economic weapon — tariffs — can succeed where Ukrainian drones and rockets haven’t, and finally persuade Putin to end his war.

In his call with Ukrainian President Volodymyr Zelensky, Trump was "merely asking a question, not encouraging further killing", the White House told the BBC in a statement.