Russia signed a strategic partnership treaty with Iran on Friday that follows similar pacts with China and North Korea. All three countries are adversaries of the United States, and Russia has used its ties with them to help blunt the impact of Western sanctions and boost its war effort in Ukraine.

The loose arrangement of hostile powers could pose a series of conundrums for President-elect Donald Trump’s pick for secretary of state.

Russian President Vladimir Putin and his Iranian counterpart Masoud Pezeshkian on Friday signed a 20-year strategic partnership treaty that includes closer defence cooperation, something likely to worry the West.